On Saturday evening, several young people fought in the Niddapark in Frankfurt.
Several people were slightly injured, one person was taken to a hospital.
It was initially unclear how many were injured.
According to the police, there were about a hundred people in the park, but not all of them were involved in the brawl.
Various crimes were committed in the evening, including robbery.
It was still unclear on Sunday morning whether the robbery was the trigger for the altercation.
The situation was unclear, as a spokesman for the police said.
The officials arrived with a large contingent and were able to calm the situation.
Numerous place references were pronounced.
The investigations are ongoing.
Last year there was a series of robberies of young people in Günthersburgpark, another Frankfurt park in the north end.