Paris (AFP) - France's failed Socialist presidential candidate Benoit Hamon on Saturday announced his departure from the crisis-hit party to establish a new "First of July movement" aimed at rebuilding the ailing left.

"Today I have decided to quit the Socialist Party. I am leaving the party but I am not giving up on the socialist ideal," said the 50-year-old as he launched his new movement before a 11,000-strong crowd in Paris.

"The Socialist Party has perhaps had its time... My belief is that it is time to turn the page," said Hamon who was the surprise winner of the Socialist nomination for president but who crashed in the first round of the vote in May.

Scoring just 6.2 percent, he finished a humiliating fifth as voters abandoned the former ruling party which has been crippled by deep ideological divisions.

Hamon's announcement came just days after former premier Manuel Valls said he was quitting the Socialist Party to be allied with President Emmanuel Macron's centrist Republic on the Move (REM).