Frank compares the 20-year-old defender to Paris Saint-Germain's Nuno Mendes, who is considered one of the best in the world at left back.
He explained: "I think the player who Mathalie has been most compared to is Nuno Mendes, so with all dimensions considered in terms of style of play, I think you can imagine what type of style and attributes you're going to find in a player like Mathalie.
"I think the price nowadays for players of his age coming from France especially comes a lot with the potential that there is behind the player and I think in terms of full-back, I think in my opinion he's got the most potential on the market at the moment.
"The high price is if you're going off potential and you also have to take into consideration that due to the French national team's lack of players in his position, he could be a part of Zinedine Zidane's squad this season.
"As soon as he makes that call-up to the France squad, his price will take a big increase. Signing him before he makes that France senior team debut is definitely a good move from my point of view.
"I think Methalie has been mentioned for some time as a serious candidate for the France team. He has been linked with a lot of top clubs in the past and the expectations with the France fans are the highest we have seen with a full-back prospect for a while."
Is gap between Champions League and Championship getting smaller?published at 08:09 BST 18 August
08:09 BST 18 August
Chris Collinson BBC Sport statistician
Image source, Getty Images
Last season, the Premier League was arguably more competitive than it has been for years.
While the 65 points between champions Arsenal and bottom side Wolves was around the average for a 38-game season (63), a real revolution took place in mid-table.
Since the league was reduced to 20 teams in 1995-96, the gap between the top four and the bottom three – between what has often been the Champions League and the Championship – had been increasing as the seasons went by, with the 'bigger' clubs profiting from their European adventures and the extra money they earned by regularly finishing higher in the table.
But last season, the gap between the 'haves' and the 'have-nots' of the Premier League dropped from 44 points in 2024-25 to just 26 points – the smallest distance for 23 years (since 25 points in 2002-03).
The European places were more attainable than they had been for years. Despite taking a point fewer than when they finished seventh the season before, Aston Villa clinched Champions League qualification by finishing two places higher.
While Liverpool took the 'bonus' Champions League place by finishing fifth, their points total of 60 was the lowest by a side finishing there for 19 years and would have put them ninth in 2024-25.
Bournemouth and Sunderland also took full advantage of needing fewer points than normal by qualifying for European competition for the first time ever and for over half a century respectively.
Sunderland come from behind to beat Rennes in final pre-season friendlypublished at 20:20 BST 15 August
20:20 BST 15 August
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Sunderland boss Regis Le Bris says his side "imposed ourselves well" to come from a goal down and beat Ligue 1 side Stade Rennes 2-1 in their final pre-season friendly at the Stadium of Light on Saturday.
The Black Cats trained 1-0 to a first-half penalty but dominated the second period, turned the game around through goals from Brian Brobbey and Trai Hume.
"It was a good second half performance - in line with our standards," Le Bris.
"Rennes are a good team, as expected. They're good with the ball and good under pressure.
"We made it a bit easy for them in the first half.
"We needed to lift the intensity at half-time and we did just that. We imposed ourselves well in the second half.
"We had to show more aggressiveness and the second half showed what we can do when we play at high pressure.
"The subs made a good impact too - that's a good sign for the season ahead."
How much will Europe affect Sunderland's second season?published at 18:06 BST 14 August
18:06 BST 14 August
Chris Collinson BBC Sport statistician
Image source, Getty Images
The belief that promoted sides that stayed up in their first season are often relegated in their second is a popular one, with the phrase 'second-season syndrome' regularly thrown about. But is it as common as people think?
Last season Sunderland and Leeds United became the 53rd and 54th promoted sides to survive in the Premier League.
Of the previous 52, only 11 were relegated the following season (21%). The vast majority of promoted teams that stay up do not suffer from second-season syndrome.
However, there is precedent for a promoted side that had a first season as good as Sunderland's to be relegated in their second. In fact, the best promoted side in the 38-game era of the Premier League did just that.
George Burley's Ipswich Town ended the 2000-01 campaign fifth with 66 points - the highest finish and most points any promoted side has achieved in a 38-game season.
But with European football to contend with, they dropped 13 places and took 30 fewer points the next season as they were relegated in 18th place, with Sunderland the beneficiaries as they finished just one place above them.
Overall, four of the previous 20 promoted sides (20%) that finished in the top half in their first season suffered relegation in their second, with the most recent example being Sheffield United five years ago.
Sunderland will be playing in Europe this season for the first time in 53 years, with at least eight games in the Europa League on top of their usual domestic commitments.
They are the 10th promoted side in Premier League history to qualify for Europe and just the fifth to do so through their league position, with the others qualifying via cup competitions or fair play.
Despite their squads arguably being the least-prepared to handle the extra fixtures, five of the previous nine teams achieved another top-half finish and just two were relegated - Ipswich in the early 2000s and Hull City in the mid-2010s.
Sunderland will be hoping to follow the example of the most recent promoted side to qualify for Europe - Wolves in 2019.
Despite playing 17 games as they reached the Europa League quarter-finals in 2019-20, they still had enough in the tank to finish seventh in the league again.
There are definitely the ingredients for Sunderland to have a difficult second season, but given how well-run they have been in their recent rise from League One to Europe, many fans will have faith they will continue to thrive.
'No anxiety' from Le Bris over lack of signingspublished at 16:44 BST 14 August
16:44 BST 14 August
Image source, Getty Images
BBC Radio Newcastle's Sunderland commentator Nick Barnes says there is "no anxiety" from Regis le Bris and those around him, despite the lack of signings so far this summer.
Thomas Meunier, on a free, remains the only incoming thus far in the window, but Barnes believes the club will still land their transfer targets.
"There's general frustration all round with trying to get players out and trying to get players in," he said.
"The general mood of Sunderland fans at the moment is there's a slight anxiety over the fact that there's still no new faces after the arrival of Meunier.
"Le Bris has said that they are working hard behind the scenes and we're hearing the players they are linked with and the knockbacks they're getting from some and the fees some clubs want.
"I'll reiterate again, Le Bris was very relaxed after Lens on Saturday and says they will get these players in and he's happy to start the season with the squad that he's got.
"He's repeatedly said, even from the end of last season, that the team that starts will probably be much the same that beat Chelsea on the last day of the season.
"I'm still fairly confident they will get these players in by the end of the window and and then Regis will have the squad he wants to to work, with the numbers that he wants to work with, because he's been very clear about having a core squad of 20.
"There's this frustration, there's anxiety, from fans but there are still three weeks of the window to go.
"Reading the the body language of Regis and those around him, there's no anxiety from their perspective.
"Le Bris, ideally of course, would have wanted these new players in already but they're not rushing. I think it's totally different to last summer where it was an influx of players straight away."
Hjelde leaves Sunderland with 'cult status'published at 13:05 BST 13 August
13:05 BST 13 August
Image source, Getty Images
Leo Hjelde's exit to Belgian Pro League side KV Mechelen has sparked the conversation at BBC Radio Newcastle around his cult hero status.
The Norwegian centre-back featured 19 times for Sunderland in the Championship in 2024-25 on their way up to the Premier League, before going on loan to Sheffield United last season.
While the 22-year-old missed out on playing in the top flight, football commentator Nick Barnes believes Sunderland fans can agree that without his contributions towards the end of their promotion campaign, they may never have made it back up in the first place.
Barnes said: "Someone posted on social media: 'No Leo Hjelde, no Dan Ballard goal, no Ballard goal, no Tommy Watson winner, no Watson winner, no promotion, no promotion, no Granit Xhaka, no Xhaka, no Europa League so therefore, no Hjelde - no Europa League'.
"So you can see how that can be fashioned into cult status for Hjelde because, not only did he come on as a substitute a minute before Ballard scored that goal at the Stadium of Light to get to the play-off final, he came on a minute before Tommy Watson scored the winner at Wembley as well.
"So he has engineered himself into a sort of niche, if you like, within Sunderland's history for being that bit-part player at the end of both those two play-off games."
Listen to the full clip below by pressing play below or on BBC Sounds here
What do the numbers say about Sunderland's 2026-27 season?published at 10:08 BST 13 August
10:08 BST 13 August
Chris Collinson BBC Sport statistician
Image source, Getty Images
Why - outside newly promoted teams Hull City, Coventry and Ipswich - are Sunderland once again among the bookmakers' favourites for the drop?
While results and where you finish in the table are ultimately all that matter, Sunderland's underlying statistics from last season suggest repeating their success might not be so simple.
Expected goals (xG) tells us how well teams do the basics of creating lots of good chances and limiting their opponents to few low-quality ones, based on how hundreds of teams before them have scored or conceded from those opportunities.
Only relegated Burnley and Wolves had a lower xG difference than Regis le Bris' side last season, while West Ham - with the fourth-worst overall xG - were also relegated.
While Aston Villa and Sunderland made a mockery of xG by finishing much higher in the table, the majority of sides finished mostly in line with their underlying numbers, showing those two overachievers were more the exception that proves the rule.
Only Manchester City and Villa overperformed their xG numbers by more than the Black Cats, who scored three more goals and conceded six fewer than expected given the number and quality of shots taken.
So taking the season as a whole, it seems that Sunderland's performances weren't as impressive as their results. But one event significantly affected part of the Black Cats' season: the Africa Cup of Nations.
They were without six players - twice as many as any other side - during the tournament in December and January. While the club's performances had already declined after a strong start, they suffered even more when their squad was stretched.
But once all those players returned, Sunderland's underlying numbers improved throughout the rest of the season and they ended the campaign playing like a mid-table side.
With no Afcon this season, the Black Cats may not suffer such a drop in performance. If they continue the 2026-27 season as they finished the last then relegation should be only a remote possibility.
How do add-ons work in football transfers?published at 07:16 BST 13 August
07:16 BST 13 August
It is common practice these days for transfer fees to have performance-based add-ons. The theory is the selling club gains more if the player goes on to be extremely successful, while the buying club is to some extent protected financially if the transfer doesn't work out.
In some cases, the total value of add-ons is significant - Real Madrid could end up paying an extra £30m to Borussia Dortmund for Jude Bellingham depending on how successful he is over the course of his career in the Spanish capital, for example.
In others, like the potential £1.7m worth of add-ons Brighton's £29.78m signing of Greece Under-21 forward Charalampos Kostoulas, are less significant.
Clubs sometimes say add-ons are 'easily achievable' or 'difficult'.
Easier-to-achieve add-ons can include things like making a basic number of appearances, or scoring a certain amount of goals. Add-ons can also be attached to a team's success rather than the individual player's - a club may agree to an add-on requiring an extra payment if they qualify for Europe, for example.
Others can be more ambitious - tied to extreme levels of individual or collective success, like winning the Champions League or the Ballon d'Or.
An example of the difficulty add-ons can present when discussing valuations would be the claims made in the Portuguese media in 2022 that the first additional payment in Darwin Nunez's £64m-plus-add-ons move from Benfica to Liverpool was triggered by the Uruguayan making just 10 appearances.
Then Liverpool boss Arne Slot rejected speculation he had not started Nunez in some games because it would trigger an additional payment.
Whether Liverpool paid more for Nunez, or club captain Virgil van Dijk - for whom they paid a flat fee of £75m to Southampton in 2017 - cannot be determined without knowing exactly what add-ons were included in the Nunez deal, then figuring out which conditions he has and has not met.
'Second season syndrome is lazy punditry'published at 13:44 BST 12 August
13:44 BST 12 August
Media caption,
"I don't think Sunderland will be anywhere near the relegation zone," says sports journalist Ian Murtagh, despite Regis le Bris' side "entering the unknown" after securing European football.
The Black Cats have gone from the third tier of English football to the Premier League, and now the Europa League, in just four years.
"Sunderland are entering the unknown in the sense that they won't just be playing 40 to 42 games this season, they will be playing over 50 games," Murtagh explained. "But it is lazy punditry to talk about second season syndrome.
"People are casting their minds back to when Ipswich Town qualified for Europe and then were relegated from the top-flight.
"But, if you look across Premier League history, only four or five sides have been relegated in their second season - and I don't think Sunderland will be anywhere near the relegation zone.
"Let's not forget the most important transfer of the summer in the north east is a non-transfer - Granit Xhaka is staying. How many Newcastle fans are sat there wishing that situation was true for them with Bruno Guimaraes?
"I do think Sunderland's hierarchy were considering cashing in on one of their prized assets, like Noah Sadiki or Robin Roefs, back in May. But I think they made a decision to stick with what they've got in the subsequent weeks.
"This side can improve. Yes they need to bring in reinforcements, but I actually think they will spend quite big by the end of this window."
Hjelde joins Belgian Pro League side KV Mechelenpublished at 12:31 BST 12 August
12:31 BST 12 August
Image source, Getty Images
Sunderland centre-back Leo Hjelde has joined Belgian Pro League side KV Mechelen on a three-year contract, with a club option for a further year.
The 22-year-old, who joined the Black Cats from Leeds United on a four-and-a-half-year deal in January 2024, only made 30 first-team appearances for the club.
Hjelde spent the second half of last season on loan with Championship side Sheffield United, however he only featured eight times for Chris Wilder's side.
'He will always have a special place here' - Ghisolfi's promise to Pattersonpublished at 17:53 BST 11 August
17:53 BST 11 August
Image source, Getty Images
Sunderland's director of football Florent Ghisolfi believes it is "the right moment" for goalkeeper Anthony Patterson "to start a new chapter in his career" after a 16-year stay at the Stadium of Light.
The 26-year-old, who joined the club's academy set-up as a 10-year-old in 2010, has penned a four-year deal with Championship club Wrexham.
Patterson made 253 appearances and kept 69 clean sheets for the Black Cats across all age groups, while also spending time out on loan with Notts County and Millwall.
"He has a special connection with Sunderland," Ghisolfi said. "He joined the academy at the age of 10, came through every stage of the club, and played an important role in some very special moments in our recent history.
"He has always represented Sunderland with professionalism and humility - and everyone at the club should be proud of his journey.
"This is the right moment for him to start a new chapter in his career. We thank him sincerely for everything he has given to Sunderland and we wish him every success at Wrexham.
'We might not sign many, but we haven't lost any' - Gabbiadinipublished at 14:51 BST 11 August
14:51 BST 11 August
Image source, Getty Images
Former Sunderland striker Marco Gabbiadini strongly supports the club's endeavours to "keep hold of their key players" ahead of the 2026-27 season, after Regis le Bris highlighted the need to be "really precise" in the transfer window.
Belgium international Thomas Meunier is the only player to arrive on a permanent deal so far, having joined on a free transfer from Lille.
"Like most Sunderland fans, I'm checking the BBC Sport website regularly just to make sure I haven't missed anything," Gabbiadini told BBC Radio Newcastle.
"We might not sign many, but we haven't lost any of our really key players either. I do think that was a worry at the end of last season because so many of our players had big seasons.
"We did have a bit of a near-miss with Granit Xhaka, but he is still at the club. That will probably be one of the biggest deals that wasn't done this summer for us."
Black Cats defender Leo Hjelde is one player who could be heading for the Stadium of Light exit doors this summer, though.
The 22-year-old is on the brink of joining Belgian Pro League side KV Mechelen, as reported by Sunderland Echo, external, after being loaned out to Championship side Sheffield United for the second half of last season.
"He is a player that hasn't pulled up any trees," Gabbiadini added. "But he has been dependable in the moments we've needed him.
"Unfortunately, the Premier League can be a cruel mistress. Once a club gets the success of getting into the top flight, some of the players do fall by the wayside.
"But hopefully he goes on and continues to have a strong career elsewhere."
Masuaku signs two-year contract at Konyasporpublished at 18:49 BST 10 August
18:49 BST 10 August
Image source, Getty Images
Sunderland left-back Arthur Masuaku has completed a move to Turkish Super Lig side Konyaspor.
The 32-year-old, who joined the Black Cats on a two-year contract in August 2025, only made four senior appearances for the club.
Masuaku spent the second half of last season on loan at Ligue 1 club Lens, having spent five years in their youth set-up, but only made six appearances in all competitions.
The DR Congo international has previous experience of playing in Turkey, having played for Besiktas between 2022 and 2025 - making 108 appearances, scoring three goals and registering 18 assists.
Sunderland 'really wanted me' - Meunierpublished at 12:01 BST 10 August
12:01 BST 10 August
Image source, Getty Images
New Sunderland signing Thomas Meunier says the Black Cats showed they "really wanted me" when they signed him as a free agent earlier this summer.
The 34-year-old is Sunderland's only permanent arrival so far this window, despite the club preparing for a return to European football.
"We got in touch already last season during the summer," Meunier told BBC Radio Newcastle.
"Lille refused because they knew that if I had to leave, they would have to spend money on another right-back. Finally we did it this summer and I have to say I had also other offers, but just playing for Sunderland - they convinced me quite quickly.
"We were back from the World Cup, they called me, it took like five minutes. Two hours later I had the first offer, six hours later I had the second offer, and the day after I was there for the medical testing.
"So, this proves as well that the Sunderland really wanted me."
Sunderland 'have to be really precise' in transfer window - Le Brispublished at 09:49 BST 10 August
09:49 BST 10 August
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Sunderland boss Regis Le Bris says recruitment this summer preparing for a Europa League campaign is "much harder" than it was before last season's Premier League return.
Defender Thomas Meunier is the only player to arrive on a permanent deal to the Black Cats so far this window, on a free transfer after his departure from Lille.
Speaking after Saturday's 2-0 pre-season win over Ligue 1 side Lens, Le Bris said: "Today, and probably in the USA as well, we showed that our squad is already well connected with good players and probably the first good recruitment is to keep your strength.
"I think at the minute it's done, which is really good, and we'll add two, three, four - we'll see. The transfer window is still unpredictable but we are working behind the scenes to strengthen the squad.
"But, it's really different if you compare with the last season.
"Here we have to be really precise and when you are looking for someone, a specific profile, it's much harder."
'I can feel the energy' - Le Bris on pre-season win over Lenspublished at 19:45 BST 8 August
19:45 BST 8 August
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Sunderland boss Regis Le Bris says the club are building for "one of the most exciting seasons for this club in over 50 years" after the Black Cats continued their pre-season preparations with a 2-0 win against Ligue 1 side Lens.
Second-half goals from Trai Hume and Wilson Isidor secured the victory in Sunderland's penultimate pre-season friendly before the beginning of a competitive season which will see them play in the Europa League.
"We are building for the season ahead - one of the most exciting seasons for this club in over 50 years," Le Bris said post-match.
"Layer by layer, step by step, we are improving every day.
"Today was a good game, a good step-up, against a very good side.
"I thought we played well; we were in control for long spells throughout the 90 minutes.
"We found solutions to score, which is always important.
"Winning games is our job, so today is another step forward, but we still have things to do. We were deserving of the victory.
"I can feel the energy of the squad, and I like the direction we are heading in. The lads are totally aware of the challenge and are working really hard. The energy, the togetherness, our connection with the fans, it feels like we have impetus.
"If we keep building on those foundations, we will have good results, for sure."
