Greek police arrested more than 100 people, including leading members of the Socialist Workers Party, at a rally on Sunday.
Cops broke up a commemoration for teenager Alexander Grigoropoulos, who was shot dead by a police officer in 2008.
Those arrested were crammed into buses and crowded police stations.
They included health workers and leading trade union activists, as well as lawyers from the successful prosecution of Golden Dawn, Thanasis Kampagiannis and Costas Papadakis.
Socialist councillors Katerina Thoidou and Petros Constantinou, and the editor of Socialist Worker’s sister newspaper Workers Solidarity, Panos Garganas, were also arrested.
Police accused the commemoration of breaking lockdown restrictions, but those arrested were released without charge.
The arrests came as Greece’s Tory-type government is trying to force through attacks on trade union organisation and the right to protest.