Marseille midfielder Joey Barton had to be pulled apart from an opposition player during a recent friendly encounter.
The one-time England international, who is on loan with the French club from Queens Park Rangers, clashed with Istre player Guy-Roland Niangbo following a tackle between the two players.
During a press conference after the match, Istre coach Jose Pasqualetti warned 30-year-old Barton that he must adapt his style if he is to be successful in Ligue 1.
"He'll have to be careful, that kind of thing does not happen in Ligue 1," he told reporters.
Barton still has five matches left to serve of a 12-game suspension that he was handed by the English Football Association for violent conduct.
The ban prevents Barton from playing in league and cup matches, but he can turn out in European encounters and friendly matches.
