French President Emmanuel Macron on Saturday denounced as an "unforgivable crime" a bloody crackdown on Algerian protesters by police in Paris 60 years ago, the strongest recognition by a French president of a massacre in which many bodies were thrown into the River Seine.

On October 17, 1961, when ordered  by then Paris police chief Maurice Papon, police attacked a demonstration by 25,000 pro-National Liberation Front (FLN) Algerians protesting against a curfew imposed on Algerians.

A statement by the French presidency acknowledged that the march was repressed "brutally, violently and in blood," noting that dozens of Algerians were killed, many others were wounded while some 12,000 were arrested.

"He admitted the facts: the crimes committed that night under the authority of Maurice Papon are inexcusable for the Republic," the Elysee Palace statement said.

The precise number of victims of the brutal crackdown was never established, with some historians putting it at over 200 dead.

This year's commemoration takes place amid diplomatic tensions between Paris and Algiers.

Early this month Algeria recalled its ambassador to Paris, citing comments attributed to Macron, who was quoted in the Le Monde newspaper as saying Algeria's rulers had rewritten the history of its colonization based on "a hatred of France."