Marseille are showing interest in Fulham's USA international full-back Antonee Robinson, while the Cottagers are considering a move for Norwich City right-back Max Aarons.
The French side are preparing for the arrival of new manager Marcelino to replace Igor Tudor, and it could mean a change in system for the club. Tudor preferred to play 3-5-2, but his successor likes to deploy a flat back four - leaving Marseille in the market for full-backs.
Nuno Tavares and Issa Kabors have both left following the expiry of their loan deals, while Sead Kolasinac is yet to extend his contract and it means they have targeted new names on both flanks.