Scuffles between Poland and Ukraine fans Tuesday prompted police in the southern French city of Marseille to fire tear gas, French media reported.
Television images showed police firing tear gas outside the Velodrome stadium in Marseille as hundreds of fans gathered before the Euro 2016 match.
At least four people were detained in the early afternoon, AFP news agency reported.
Fan violence has marred the tournament, prompting UEFA to hand down a suspended disqualification against Russia and a 100,000-euro (112,000-dollar) fine for Croatia.
Earlier in the week, Interior Minister Bernard Cazeneuve said 557 detentions of "violent supporters" have been made since the start of the Euro, including 334 who were held in police custody.