Right-wing extremists and supporters of the anti-immigrant Pegida movement took to the streets in Cologne on Saturday, attacking police with bottles and firecrackers.
The police then responded with water cannons and broke up the demonstration of about 1,700 people.
Three police officers were injured in the clashes.
The demonstrations were reportedly sparked by the sexual assaults on New Year’s Eve in Cologne.
Police say they recorded 379 cases of violence in the city — ranging from groping to theft to two reported rapes.
Some witnesses and victims say most of the perpetrators appear to be Arabs or from North Africa.
So far, German police have identified 31 suspects, most of whom were asylum seekers.
German Chancellor Angela Merkel says her party has decided to take tougher action against criminal refugees.
She says the changes are “in the interests of citizens, but also in the interests of the vast majority of the refugees as well”.