Nice and Cologne fans clashed in the stands at the Allianz Riviera stadium before their Europa Conference League match on Thursday.
Borussia Dortmund and Copenhagen fans were seen throwing flares at each other before the start of their Champions League match at the Westfalen Stadium on Tuesday.
Young Boys fans came under attack from Anderlecht hooligans in the Belgium capital ahead of their Europa Conference League tie on Thursday.
Fans of Twente and Fiorentina clashed in the centre of the Dutch city of Enschede on Wednesday.
Young Boys hooligans attacked Anderlecht fans at a bar in Bern ahead of Thursday’s Europa Conference League tie.
Brondby and Pogon Szczecin fans clashed outside the Brondby Stadium after their Europa Conference League tie on Thursday night.
Chaos erupted in the stands at the Velodrome stadium ahead of Marseille’s Europa Conference League game against PAOK on Thursday.