Some 150 Russians were behind much of the violence in Marseille ahead of the Euro 2016 match between England and Russia, French prosecutors have said.
Ten people, including six Britons, three French and an Austrian, face an immediate trial, Marseille prosecutor Brice Robin said.
But he said just two Russians had been arrested, both for a pitch invasion.
About 35 people have been injured, including four whose conditions were said to be serious, after the violence.
This comes after the two teams drew 1-1 on Saturday.
‘Extremely well trained’
Mr Robin told a news conference. “These people were well prepared for ultra-rapid, ultra-violent action.
“These are extremely well trained people.”
Most of the 35 people who were injured in the fighting were English, Mr Robin said, adding that two Russian nationals were being expelled from the country.