Police say eight officers were injured in clashes with football fans before the German Cup match between Eintracht Frankfurt and Kaiserslautern.
The two clubs have a long history of animosity between their fans. Clashes between rival groups apparently left more people injured but police had no figures.
Police say they were attacked with stones, bottles and firecrackers, and responded with batons. Eight people were arrested. One woman was seriously injured when she fell onto railway tracks.
Second-division Eintracht lost 1-0 in extra time on Wednesday.