Crystal Palace had an offer of €14 million plus €4 million in add-ons rejected by the Ligue 1 club over the summer, while Fulham were prepared to go as high as €20 million for the defender, but Brest turned down both approaches. Sporting legal director Jules Diatta has since revealed just how close the club came to a record sale.
"The president said he wasn't selling," Diatta said. "That doesn't stop interested clubs from making offers. But there was no set price.
"There were offers for significant amounts; I think if we had sold him this summer, we would have broken the club's transfer record."
That record, €15 million from Romain Faivre's move to Lyon in 2022, remains intact for now, with Brest choosing stability over an early payday for one of their most promising academy graduates.
According to Le 10 Sport, however, Palace have no intention of dropping their interest and remain "very interested" in the 20-year-old, with suggestions that matters "could get more complicated" for Brest when the January window opens.
The report claims Le Guen held talks with head coach Pierre Sage during the summer, raising the possibility of Crystal Palace returning with an improved bid, potentially alongside a renewed push from Fulham. Other unnamed clubs are also said to be monitoring the situation.
Brest are aware of the growing interest and are working on improving the terms of Le Guen's contract, which currently runs until 2029, though there is no guarantee that alone will be enough to keep hold of him. The centre-back made his senior breakthrough only in the closing weeks of last season, making just six Ligue 1 appearances, but his rapid rise, allied to his imposing physical profile at close to 1.98m tall, has made him one of the most sought-after young defenders in Ligue 1.
Arsenal were also credited with an interest in Le Guen over the summer, as Mikel Arteta's side looked for defensive cover following William Saliba's injury, though it was Palace and Fulham who pushed hardest for his signature.