Marseille sporting director Jose Anigo has praised Barton and suggested the Ligue 1 club would be interested in retaining the midfielder beyond his season-long loan from QPR.
"He was described as an animal, but he is just the opposite. He is funny, intelligent, and he fights for victory," Anigo told L'Equipe.
"We can see that the team has been lifted by his competitive spirit. He is now established as a leader in our group.
"He is very happy here, maybe he has found the right club for him. Should he desire (to stay) it could be very good. We have a very good relationship with his club QPR."