The 150 Russian football supporters “were well prepared for ultra-rapid, ultra-violent action” and were able to evade arrest, Marseille prosecutor Brice Robin said, BBC reports.
Ten people – six Britons, three French and an Austrian – face immediate trial.
Two Russians have been arrested, both for a pitch invasion.
The clashes in the stadium on Saturday followed England’s 1-1 Euro 2016 draw with Russia, after Russia fans appeared to rush at England supporters.
About 35 people have been injured, four seriously, and a total of 20 people have been arrested in connection with the violence.
Police have deployed tear gas to disperse football fans on a number of occasions over the past three days.
Mr Robin told a news conference: “There were 150 Russian supporters who in reality were hooligans. These people were well prepared for ultra-rapid, ultra-violent action. These are extremely well-trained people.”
This was what made it difficult to arrest them, the prosecutor said, adding that he did not think the Russian hooligans were “professional” but that they “were extreme”.
Mr Robin said images were being analysed at Marseille’s urban surveillance centre.
He said police officers were looking at the pictures to identify with their foreign colleagues – Russian and English football spotters – to see if these people could be identified.
Britain’s Assistant Chief Constable Mark Roberts, the National Police Chiefs’ Council lead for football policing, has appealed for fans with their own camera phone footage to contact crime-fighting charity Crimestoppers.