The suit concerns both the extensive and unthinking use of chemicals in the centre of Athens, the infliction of injuries, serious bodily damage and disablement involving reporters, photo-journalists and media enterprise staff.
Among their number was Manolis Kypraios, who was rendered completely deaf with a flash grenade went off inside an arcade just centimetres from where he was standing, even though he had displayed his press ID to police.
"We were also among the 'collateral damage' of the unrestrained violence of the MAT riot police, which exceeded all precedent in the last two decades," said a journalist at a press conference held by POESY at the headquarters of the Athens Union of Journalists (ESHEA).
According to the head of the Greek photo-journalists union Marios Lolos, Athens was currently more dangerous for
journalists than a war zone, since police were deliberately targeting photo-journalists and treated a camera as a weapon.
ESHEA board member Dimitris Trimis said a political order had been issued to evacuate Syntagma and accused the government of creating "conditions of civil war".
The Greek unions have also reported the incidents to the International Federation of Journalists and the European Federation of Journalists.
The suit will be filed at the Supreme Court public prosecutors' office on Wednesday.