Legia's away game against Lech Poznan was abandoned on Sunday after Lech hooligans threw smoke bombs and invaded the pitch.
Hammarby and AIK fans confronted each other inside the Tele2 Arena after the final whistle of their Allsvenskan clash on Sunday.
Marseille fans clashed with riot cops in the Old Port area of the southern French city after their team's defeat to Atletico Madrid in the Europa League final on Wednesday night.
A group of Lausanne-Sport hooligans attacked rival Thun fans during their Super League clash on Sunday.
A Dinamo Bucuresti fan pinched a Hungarian flag from Sepsi supporters during their Liga 1 clash on Monday.
Djurgardens and Hammarby fans briefly clashed in the stands at the end of their match on Sunday night.
Sparta Prague fans caused trouble at the Mestsky Stadium in the northeastern Czech city of Ostrava during Saturday's clash with Banik.
"Football Beasts", a new RT documentary on football hooligans in Europe that was released on Wednesday.
Schalke and Eintracht Frankfurt hooligans clashed in the stands following the full-time whistle of their DFB Pokal match on Wednesday.
Crvena Zvezda fans attempted to attack rival Partizan supporters at the Rajko Mitic stadium during Saturday's Belgrade derby.
CSA Steaua and Academia Rapid fans clashed in the stands at Bucharest’s Arena National during their Liga IV match on Saturday.
Borussia M'gladbach hooligans managed to pinch a Köln flag during Köln's away match against Hoffenheim on Saturday.