The mayor of the Brussels district of Anderlecht banned both the meeting and any street protests planned in connection with it, the Belga news agency reported.
Organisers of the so-called "European Dissidents' Congress" had kept its venue secret until the last moment to try to avoid a ban. The meeting aimed to bring together a string of controversial far-right figures that included comedian Dieudonné M'bala M'bala, who has faced repeated convictions for anti-Semitism, Holocaust denial and incitement to racial hatred in France.
The Belgian League against anti-Semitism, LBCA, on Friday filed a complaint before the Brussels prosecutor against what it warned would be "a day of hate, that would serve as a platform for the worst gathering of anti-Semite authors, theorists and propagandists that our country has seen since the end of World War II".
The Simon Wiesenthal Centre for Holocaust studies and human rights rallied behind the calls for a ban.
"The fact that this hatefest is to be held in Brussels, the capital of Europe, the seat of its Parliament ... is a threat to democracy reminiscent of the 1920s Weimar Republic, which brought Europe to the Nazi abyss," the centre's director for international relations, Shimon Samuels, said in a statement.
Several hundred people who had planned to attend the meeting gathered in Anderlecht, watched by a line of riot police, while the organisers 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.
Comment: Strange that Jewish groups should lead the efforts to block this public meeting. Don't they like democracy?