Police used water cannon on Sunday to disperse a crowd after authorities banned a rally in Brussels that a French comedian accused of anti-Semitism was due to address.
Eric Tomas, mayor of the Brussels suburb of Anderlecht, told Reuters he had issued an order prohibiting the "First European Dissidents' Congress" scheduled to be held in the area on Sunday because there was a clear risk of a disturbance to public order.
The event, organized by a small far-right group, "Stand up Belgians!", was to have been addressed by speakers including French comedian Dieudonne M'Bala M'Bala, according to the group's web site.
Dieudonne has been repeatedly fined for "hate speech" in his native France where local authorities in several towns have banned his shows as a threat to public order.
He is closely associated with the "quenelle", a gesture that critics have likened to an inverted Nazi salute and said carries anti-Semitic overtones. He denies he is anti-Semitic.
The Belgian League against Anti-Semitism had lodged a legal complaint against the meeting, describing it as a "real day of hatred which would be a framework for the worst gathering of anti-Semitic authors, theoreticians and propagandists in our country since World War Two".
Several hundred people who had planned to attend the meeting gathered in Anderlecht, watched by a line of riot police, while the organizers appealed to Belgium's top administrative court, which did not immediately rule.
After a standoff lasting several hours, the police moved in with water cannon to disperse the crowd.
"We have seen a total demonstration of anti-democracy ... We are in the Soviet Republic of Belgium. All our rights are flouted," Laurent Louis, an independent member of the Belgian parliament who chairs the "Stand up Belgians!" group, told supporters afterwards.