The English Football Federation forwarded the suspension to its French equivalent and they used Article 12 of the Regulations for the Status and Transfer of Players from FIFA, which means that the ban is applicable in a differing country.
Having already served three games of the ban while waiting for the loan move to go through, the new ruling will see Barton miss nine games in either Ligue 1 or the Coupe de la Ligue; however, he could still play in the Europa League.
The ban was initially imposed by the FA after the midfielder was found guilty of two counts of violent conduct for the incident surrounding his sending off against Manchester City during the final game of last season.
The 30-year-old could now make his debut for his new club on September 20, when the French outfit faces Fenerbache in its Europa League opener.
Follow GOAL.COM USA on