Former Education Minister Benoit Hamon and former Prime Minister Manuel Valls topped the list after the first round of the French Socialist Party primaries held on Sunday.
Hamon, with the left wing of the Socialist Party, so far has obtained 35 per cent of the votes doing especially well among young, urban voters, EFE news reported.
The more centrist Valls — well-known because of his stint as Prime Minister from 2014-2016 — obtained about 32 per cent votes, falling to second place against all predictions, with about 18 per cent going to former Economy Minister Arnaud Montebourg, who was also one of the three favourites.
More than 7,500 polling stations collected votes in continental France and its overseas territories.
With none of the candidates exceeding 50 per cent of the votes in the first primary round, French voting rules mandate that the two top vote-getters face off in a run-off on January 29.
“By placing me in the lead, you sent a clear message of hope and renewal. You have expressed your desire to open a new page for the Left,” Xinhua news agency quoted Hamon as saying.
“We must finish with the old recipes, the old politics. I will continue to defend the priority given to the social issue, ecological conversion and democratic renewal,” he told his supporters.
Long trailing his rivals in opinion polls, the 49-year-old left-winger has seen his ratings unexpectedly start surging a few days ahead of the contest after three televised debates gave him impetus.
Hamon is likely to pass the Left primary runoff with a strong lead thanks to the backing of defeated candidates including Montebourg.
“Primary voters have spoken … They massively and seriously condemned the mandate (of the Socialist President Francois Hollande),” Xinhua news agency quoted Montebourg as saying after the release of the partial results.
“Next Sunday, I will vote Benot Hamon and I invite you to do the same,” Montebourg said.
Losing momentum, Valls said that for the second round, “nothing is written.”
“A new campaign begins this evening. A very clear choice is now for you and for us,” he said.
Dominating France’s political landscape for decades, the Socialists and the broader Left are weakened by internal upheavals that it has been hard for them to build momentum to take on the right-wing and the far right party.
No left-wing candidate is likely to pass to presidential runoff on May 7 after Hollande’s policies had alienated left voters, the country’s pollsters predicted.
The primary is the second such competition held by the Socialist Party and allies.
In 2011, the Socialist Party had opened a two-round contest to all registered voters regardless of their political views as long as they share the left-wing values and donate 1 euro (1.069 U.S. dollar).