Marseille say they will investigate the incident which saw Patrice Evra aim a kick at one of his own supporters.
Evra was sent off before their Europa League defeat to Vitoria Guimaraes for a karate-style kick at a Marseille fan.
It followed a heated exchange with a group of visiting supporters fans on the touchline before kick-off.
Marseille said in a statement: “Olympique de Marseille has noted the altercation between an individual and Patrice Evra during the warm-up at the game against Guimaraes (on Thursday).
“An internal investigation has been opened to establish responsibilities.
“No matter what happens, a professional player must maintain self-control despite provocations and insults, no matter how unjustified they may be.”
UEFA say they will wait for the referee’s match report before deciding whether to open an investigation.
Evra was confronted by a group of supporters who had managed to get out of an area reserved for around 500 Marseille fans, who had travelled to Portugal for the game.
Stewards at the ground quickly intervened to break up the trouble, with Evra, who was originally listed as a substitute, ordered to return to the dressing room by the referee.
Marseille coach Rudi Garcia said: “Pat (Evra) has experience, and he must not react, it’s obvious.
“Patrice is a more than just an experienced player. You can’t respond, of course, to insults as bad as they are and as incredible as they might be because they come from one of our supporters.
“He must learn to keep his cool. That’s all I can say.”
Garcia, however, criticised the fan who taunted Evra at the D. Afonso Henriques stadium.
He added: “He’s not a supporter of Marseille, because you can’t insult your own players, you have to be behind all of us.”
The incident immediately brought back memories of another act of kung-fu kick madness by a French footballer.
In January 1995, Manchester United forward Eric Cantona launched a flying kick at a Crystal Palace supporter at Selhurst Park who had jeered him after he had been sent off.
Cantona’s assault led to a nine-month ban handed down by the English Football Association.