The 30-strong hooligan gang threw bottles and smashed up a bar while the travelling support were relaxing at British style pubs in Lyon.
Three Lions fans were soaking up the pre-match atmosphere in a quiet square ahead of tomorrow night's fixture with Slovakia when they were set upon at around 7.30pm.
The thugs responsible were dressed all in black with red crosses on their arms.
Witnesses say they stormed the popular tourist square attempting to rampage the visiting England supporters.
Video footage also appears to show the mob causing havoc on a narrow pedestrian-only boulevard.
The attacks occurred in Lyon, the major town and transport hub closest to St Etienne, where tomorrow's match takes place.
Bar owners in St Etienne had created a 'Glastonbury style' atmosphere in the match city with music sound systems and circus acts for fans to enjoy ahead of the game.
Tonight's attack came as concerns for the safety of Euro 2016 fans grew following lapses in security at host stadiums across France – and growing evidence of an ISIS plot to target the championship.
The regional governor responsible for St Etienne has condemned UEFA for the lax security at the city’s stadium - 24 hours before thousands of England fans will flood in.