More than 20,000 people took part in left-wing demonstrations to mark International Workers' Day, or Labour Day, in Berlin, Hamburg and other German cities on Wednesday.
The traditional rallies by workers and activists were held this year amid the backdrop of the tensions surrounding the war in Gaza.
Germany has banned or restricted pro-Palestinian demonstrations over the past seven months, often citing fears they could lead to incitement to hatred and anti-Semitic statements.
Police said a demonstration organized by the German Trade Union Confederation in Berlin was temporarily halted due to repeated pro-Palestinian chants and banners being displayed.
There was a massive police presence at the rallies, many of which were organized by trade unions to demand greater social justice and rights for workers.
Berlin police said that they were accompanying a total of 19 gatherings with 5,600 officers. There were no major reports of violence by Wednesday evening.
Water cannon, a helicopter and light masts to illuminate the streets were also on standby in case the situation got out of control.
But there was convivial atmosphere in the Kreuzberg neighbourhood, a traditional bastion of the German capital's radical and underground culture.
If not marching, many people simply partied, played music and hung about the parks and public squares, a drink in hand.
In the south-western city of Stuttgart, a demonstration by the left-wing scene in the city centre was broken up after attacks on police officers. Officers responded with pepper spray and batons.
According to the police, the demonstration was "against social welfare cuts" and campaigned "for a society based on solidarity" and had been organized by an individual.
In the northern port city of Hamburg, more than 6,000 people took to the streets in various demonstrations by leftist and anarchist groups. Some of the marches went though the posh districts of Harvestehude and Pöseldorf and included demands for wealth redistribution.