Five people were injured on Sunday after a group of eight people attacked an anti-fascist centre in the Greek port of Piraeus, police said.
The attackers, suspected of being members of the far-right, stormed the Favela Free Social Centre in the port city near Athens, holding torches and iron bars.
Two people were taken to a hospital.
"Today in the afternoon while we opened our centre for our weekly meeting, we were attacked by a group of Golden Dawn members with iron bars, helmets and flares," a post on the Facebook page of the Favela Free Social Centre read, referring to Greece's far-right, neo-Nazi party.
Among those wounded by the attackers was a woman that had a connection with Pavlos Fyssas, the anti-fascist rapper killed by Golden Dawn members in September 2013, according to police sources.
A total of 70 Golden Dawn lawmakers and party officials are on trial on a wide range of charges, including membership of a criminal organisation linked to the fatal stabbing of Fyssas and several other charges.
The neo-Nazi party remains the fourth largest in the Greek parliament.
The Favela centre was also attacked last August, and four people were arrested by the counter-terrorism unit, according to Athens News Agency.