Barton launched a series of tirades against the club via Twitter after he was forced to train with the youth team, but he appears to be leaving the west London club on good terms after finalising a temporary move to the Ligue 1 leaders while Stephane Mbia has gone in the opposite direction in a permanent deal.
"I am now a player for L'OM. What a birthday present! Cannot wait to get going. #allezL'OM," tweeted Barton, who turns 30 on Sunday.
"Would like to thank (agent) Willie Mckay, (Marseille sporting director) Jose Anigo and (chairman) Vincent Lebrune aka Mr President for making it happen. #allezmarseille
"I would also like to thank (QPR owner) @tonyfernandes and (chief executive) @Amit_Bhatia99 for making this possible. Good luck to everyone at QPR for this season.
"I am happy to be playing for such a massive European club like Marseille. Bonne nuit xx"
Source: PA
Source: PA