The overnight violence follows weeks of escalating tensions around a building that is a centre of the far-left youth scene. It has been repeatedly raided by police.
Police said yesterday night's protest was the city's "most aggressive and violent demonstration in the past five years".
Police had sent 1,800 officers to confront the 3,500-strong crowd. The officers used batons and tear gas as the situation deteriorated.
Eighty-six protesters were temporarily detained, with three facing a magistrate on charges of breach of the peace, police said.
The city-state's minister in charge of security, Frank Henkel, denounced the "orgy of violence of the extreme left" by "anarchists and troublemakers".