The 19-year-old made his debut for Brest during the 2025-26 season and went on to make six Ligue 1 appearances, starting the club's final four matches of the campaign, including fixtures against Paris Saint-Germain and Strasbourg.
Crystal Palace have enjoyed recent success signing young centre-backs from France, with 19-year-old Jaydee Canvot arriving from Toulouse last year and quickly establishing himself as a mainstay of the backline following the departure of former captain Marc Guehi to Manchester City in January.
Palace are also continuing talks over Augsburg defender Chrislain Matsima as a more direct potential replacement for Lacroix, whose exit to Chelsea is understood to be advancing towards completion, with a medical having been scheduled in recent days. The 24-year-old former France youth international is open to a move to Selhurst Park, where he would work under compatriot Pierre Sage, appointed Palace manager earlier this summer following Oliver Glasner's departure at the end of his contract.
Matsima made 48 Bundesliga appearances for Augsburg last season after joining from Monaco, though a serious tendon injury sustained in January kept him sidelined for around four months as Augsburg finished tenth in the table.
He remains under contract in Germany beyond this summer, meaning any deal would require Palace to negotiate a fee with the Bundesliga club rather than simply agree personal terms with the player.
Sage is keen to have defensive reinforcements in place before the new Premier League season begins, with Lacroix having been a key figure in Palace's run to Conference League glory last term, a triumph that came alongside FA Cup and Community Shield successes during his time at Selhurst Park.
Oscar Mingueza, signed from Celta Vigo on a free transfer, has so far been Palace's only confirmed defensive addition of the summer, with the club expected to move quickly on further reinforcements once the Lacroix sale is finalised.