A 50-year-old England supporter is fighting for life at a hospital in Marseille after he was beaten by a group of Russian fans before a Euro 2016 game.
The clash happened prior to the Group B match between England and Russia, Marseille's police prefect, Laurent Nunez, said.
The Englishman, who suffered a heart attack and was resuscitated by police, was rushed to a hospital in a critical condition.
The beating occurred near the Vieux-Port district of downtown Marseille when fans clashed hours before the start of Saturday night's (Sunday AEST) match at the Stade Velodrome, which ended in a 1-1 draw.
Authorities said the man received several blows with a metal bar, some to the head.
A total of three English fans were hospitalised with serious injuries, Marseille's city government said.
The opposing fans squared off in a pitched battle in the city's downtown for several hours despite the deployment of riot police, who used tear gas and water cannon.
It was a third consecutive day of violent incidents in Marseille.
French Interior Minister Bernard Cazeneuve condemned the violence, blaming it on "pseudo-fans."
A man is arrested by police officers in downtown Marseille, France, Saturday, June 11, 2016. Source: AAP
"Once again, as over the last 30 years, an international football competition has been the scene of clashes between violent people claiming to be supporters of their national team," he said in a statement.
Amid the broken beer bottles and grey clouds of tear gas that filled the air during the afternoon, families and tourists walked around the picturesque port, sometimes forced to skirt around lines of riot police leaning on their shields.
Groups of people watched the chaos from the rear decks of two gleaming white yachts.
TV footage showed fans throwing chairs yanked from restaurant terraces and scuffling on a staircase, where one man was seen kicking another one down the stairs.
In Nice, Northern Ireland fans clashed with locals in the French city on Saturday, BFM TV reported, hours after the violent skirmishes between English and Russian supporters.
Seven people are believed to have been injured in Nice with bottles and chairs thrown as riot police moved in to contain the scuffles.
Police absolutely nowhere to be seen. Been going on for about 15 minutes. #Marseille #Russia #England #euro2016 pic.twitter.com/IIGiCFvED2 — Robert Anderson (@RAMCMXCV) June 11, 2016
