Designated as high risk beforehand due to the rivalry between the teams' fans, the match was halted for around 30 minutes at the end of regulation time with the scores locked at 0-0.
Police said fans from the visitors' end fired flares toward the main stand, with home supporters then storming the pitch in response.
"A total of 85 people required medical attention, with eight transported to the hospital for further treatment," the police said in a statement.
The match was continued after a "massive police intervention on the pitch to force individuals back toward the home supporters' section using physical measures".
Almost 1,400 police officers were deployed to provide additional security at the match between the rival clubs located around 50 kilometres apart.
The match finished 1-0 after Kaiserslautern's Ibrahim Kanate scored in the 120th minute.