President Emmanuel Macron has described the deadly crackdown by Paris police on a peaceful protest by Algerians as "unforgivable for the republic", going further than his predecessors in admitting crimes which French authorities had covered up for decades.
Macron told relatives and activists on the eve of the 60th anniversary of the bloodshed that "crimes" were committed on the night of 17 October, 1961, under the command of Paris police chief Maurice Papon.
He acknowledged that several dozen protesters had been killed, "their bodies thrown into the River Seine" and he paid tribute to the memory of the victims.
While the precise number killed has never been established, in-depth research by leading historians suggests at least 200 were shot dead.
Macron "recognised the facts: that the crimes committed that night under Maurice Papon are unforgivable for the republic," the Elysee said, adding that "this tragedy was long hushed-up, denied or concealed".
Macron, the first French president to attend a memorial ceremony for those killed, observed a minute's silence in their memory at the Bezons bridge over the Seine on the outskirts of Paris where the protest began.
His comments that crimes were committed went further than predecessor Francois Hollande, who in 2012 acknowledged that the protesting Algerians had been "killed during a bloody repression".
However, as expected, the French president issued neither a formal apology nor gave a public speech.
Some survivors of the 17 October massacre and their descendents have been campaigning for France to officially recognise its responsibility in what happened.