Romania police arrested and fined 20 Rapid Bucharest fans for hooliganism after disturbances following their team's 3-0 win over Sportul Studentesc at the weekend, a club spokesman said.
"Fans attacked policemen with stones apparently without any reason," Cristian Costache said.
"Police reacted with tear gas and there was a fight between fans and policemen outside the ground late on Sunday night."
Sunday's violence followed clashes on Saturday between fans of Dinamo Bucharest and Universitatea Craiova. A referee was also assaulted by National Bucharest fans after their team lost a match against Dinamo Bucharest.
Dinamo played their home match in Ploiesti, 60 km north of the capital as punishment for racist abuse from their fans towards an Ivory Coast player last month.
Steaua Bucharest were also penalised for racist behaviour at an earlier game and played their match against Jiul Petrosani behind closed doors.