Marseille suspended Patrice Evra indefinitely on Friday while they investigate an incident in which he aimed a kick at a fan ahead of a Europa League game.
The French club said they would interview Evra before deciding upon disciplinary action.
Evra, named as a substitute for OM's fixture away to Guimaraes, lashed out at a Marseille fan in a heated confrontation before Thursday night's match in Portugal.
Video footage showed Evra aiming the kick at the Marseille fan as visiting players and supporters confronted each other at the side of the pitch. He was then ushered away by a teammate.
The former Manchester United defender was sent off and on Friday UEFA announced the 36-year-old would miss "at least one match" with further punishment likely to follow.
In a statement, Marseille condemned Evra's reaction but also said they were launching an investigation and would take legal action against the fans who antagonised the player.
"Jacques-Henri Eyraud, Olympique de Marseille president, met with Patrice Evra today and suspended him internally with immediate effect and with a summons to an interview ahead of potential disciplinary action," the statement said.
"Additionally, the early results of an internal investigation conducted by the club have revealed the unacceptable behaviour shown by a handful of provocative people slewing heinous insults particularly serious towards the player while he and his teammates prepared for an important match.
"As a professional and experienced player, Patrice Evra should not have responded in a manner that was also inappropriate.
"The club's investigation continues and will exercise the means at its disposal against the individuals who, using a passion for Marseille as a disguise, put OM's reputation in danger by entering the pitch and insulting a player instead of providing support."
Former France captain Evra, who won five Premier League titles and the Champions League during an eight-year spell with United, joined Marseille from Juventus in January, but has made just two appearances for the club in all competitions this season.
UEFA also charged Marseille with breaches of Article 16 of its disciplinary regulations, namely the "field invasion by supporters, the setting-off of fireworks and acts of damages."