Pro-Kurdish demonstrations have also taken place elsewhere in Germany this weekend.
Some 200 people marched through the capital, Berlin, on Sunday, waving red, white and green Kurdish flags. Some demonstrators were reported by DPA news agency to have thrown rocks at a building after a man waved a Turkish flag from there.
Riot police were said to have led several men away, but there were no official reports of arrests or injuries.
In the northern city of Hamburg, some 400 protesters marched to the Russian and Turkish consulates general late on Saturday. A police spokesman said some threw rocks at the buildings, causing minor damage.
Demonstrators were protesting against Russian participation in the Afrin offensive.
Other, peaceful, rallies were reported on Saturday in Kiel, Saarbrücken and Kaiserslautern.
Turkish troops and allied Syrian rebels have now moved to within a few hundred meters of the city of Afrin, according to the Britain-based Syrian Observatory for Human Rights.
Turkish armed forces launched the offensive on January 20, with Turkish President Recep Tayyip Erdogan threatening to "purge" a Kurdish militia from the town.
Ankara considers the US-backed Kurdish People's Protection Units (YPG) a terrorist group linked with the outlawed Kurdish Workers' Party (PKK), which has been waging a decades-long rebellion in Turkey.