Lille have launched a disciplinary procedure against a player, believed to be Hatem Ben Arfa, after an altercation with a team-mate and backroom staff in the dressing room last Saturday, the club's coach Jocelyn Gourvennec said on Friday.
The 35-year-old former France international only joined the 2021 French champions in January and has played for them seven times without making much of an impression.
"The club has launched a procedure which is ongoing," Gourvennec said at a press conference in which he did not name the player involved or the type of the procedure he was facing.
"The club president and directors have got involved.
"The player in question has been barred from training this week and I believe the club will issue a statement once the procedure has progressed.
"After that it will be the legal department who will manage it."
Gourvennec said he was very fond of the player involved who had behaved "inappropriately".
"However, the president (Olivier Letang) has a golden rule: you do not hurt the club, the team nor the coach," he said.
"As coach it is impossible for me to ignore something which could affect the unity within the team, the squad or the dressing room."
The much-travelled 15-times capped Ben Arfa has been a free agent since leaving Bordeaux last year.
Lille was his 10th club in 15 years as a professional.
He has also played for Paris Saint-Germain, Lyon, where he won four Ligue 1 titles, Marseille, where he also won the French league crown, English outfit Hull City and Spanish club Real Valladolid.
He shone in four seasons at Newcastle, with the club's then manager Alan Pardew comparing his skills to those of Lionel Messi and Luis Suarez.
His performances in the Premier League earned him a place in the France squad for the 2012 European Championship.
But after a successful return to France in 2015 when he scored 17 goals in 34 appearances for Nice, his career stalled in a goalless stay at star-studded PSG and he scored just twice in 24 games for Bordeaux.