Hatem Ben Arfa could take legal action against Paris Saint-Germain – after being demoted to the club's reserves.
The former Newcastle United forward is out of favour at the Ligue 1 club.
Ben Arfa chose to stay at the Parc des Princes in the summer – and in doing so scuppered a PSG move for Nice's Jean-Michael Seri.
However, Jean-Jacques Bertrand, Ben Arfa's lawyer, believes the move contravenes Ligue de Football Professionnel rules.
"Legally, I think the club is violating the Professional Football Charter," Bertrand told AFP. "I informed the club by email and advised that we do not accept the situation.
"Depending on the response, we will seek action from the league's disciplinary committee."
Ben Arfa joined PSG from Nice last summer after returning to form and fitness at the club.
The France international was controversially made to train with United's Under-21 side by then-manager Alan Pardew in 2014.
Ben Arfa was released from his Newcastle contract the following year after falling out with Pardew.