Their march on Saturday attracted an estimated 1,500 people who demonstrated against it, including what police described as some 700 from leftist groups who took part in a separate demonstration, which had been denied official permission.
The mainstream anti-fascist demonstration attracted many regional politicians, with Social Democrat (SPD) general secretary Michael Groschek calling for Dortmund citizens to set a “sign for democracy and diversity and against national socialism and xenophobia.”
Police said that as the evening drew in, trouble started between the right wing extremists and their opponents, as well as officers who tried to keep them apart.
Six neo-Nazis and 47 left-wingers were arrested, police reported.