Ten Poland and Croatia football fans have been fined for violence and public order offences in Poznan, while one Irish fan was fined for drink-driving, a court official said.
The fines relate to trouble at the Croatia-Republic of Ireland Group C match on Sunday, which the Croats won 3-1.
Two Croats who invaded the pitch were each fined 2,000 zloty (463 euros) and were banned from the Municipal Stadium in Poznan for three years
Two other Croat supporters were fined for involvement in a fight in the old city and the fifth was told to pay 1,000 zloty for breaking a car window.
Five Poles who were involved in the same fight were fined between 800 and 2,400 zloty