Dortmund and Schalke hooligans clashed at the Westfalen Stadium after their Bundesliga match on Saturday.
After the final whistle of the match, which the visitors won 4-2, a group of Dortmund hooligans made their way to the away end and clashed with their Schalke counterparts.
Riot police were called in to quell the trouble.
There were no reports of arrests.
