Patrice Evra was sent off after kicking one of his own team’s fans in the head before Marseille’s Europa League defeat at Vitoria Guimaraes.
Footage shows the 36-year-old ex-Manchester United defender aiming an acrobatic kick at a supporter at the side of the pitch during the warm-up.
Substitute Evra was dismissed before kick-off in Portugal, and Marseille started with 11 players.
Uefa’s disciplinary body is likely to rule on any further action on Friday.
French newspaper L’Equipe reported that Marseille supporters had been jeering Evra for about half an hour while the players prepared for the game, which the French side lost 1-0 after Paolo Hurtado’s late goal.