More than 2,000 police officers were in Hamburg’s most incendiary area, the Schanzenviertel from the afternoon onwards, while barricaded shop windows showed what local businesses expected.
A demonstration outside the famous left-wing culture centre Rota Flora drew up to 4,000 people, calling for the project to be maintained and other housing projects to be protected.
Such demonstrations have frequently led to violence between left-wingers and police and Saturday was no exception, with officers pelted with stones, bottles and fireworks. They reacted with water canon, eventually clearing the streets and making at least 17 arrests.
A police spokesman said 16 cars were set on fire in nine places around Hamburg on Saturday night but it is not clear whether this was connected with the demonstrations in the Schanzenviertel.
There were also a few incidents in Berlin, with a handful of arrests in the Friedrichshain district after a punk concert came to an end.
The Mauerpark in the Prenzlauer Berg district, often the scene of fighting between drunken party-goers and police, remained peaceful, with around 1,000 people braving the barriers and bag-checks erected at the entrances.
Further tension is expected on Sunday evening as street parties and political demonstrations draw to a close. The Berlin district of Kreuzberg is usually the scene for larger-scale violence on May 1, and has become an attraction for ‘riot tourists’ from other parts of the country.
There have also been warnings that this year the rioting could be worse than usual in the wake of the eviction of a long-term squat in the Friedrichshain district which led to days of protests and isolated acts of vandalism.