There were violent incidents when some 900 people took to the streets of the northern German city of Goettingen to protest a demonstration by the far-right National Democratic Party (NPD) on Saturday.
The counterdemonstrators threw stones at police and trains when some 100 NPD supporters gathered on the square in front of the central station, police reported.
Two police cars were damaged in the scuffles. The demonstrators used construction site barriers to block the train tracks, then set them alight. There were no injuries, police said.
In some cases, police launched investigations into potential breaches of the peace.
The administrative court in Goettingen had earlier banned a planned march by the NPD through the city for fear of violence and restricted them to gathering on the station forecourt.