Most members of leftist candidate Jean-Luc Mélenchon's party will abstain or leave their ballot papers blank in the presidential run-off between President Emmanuel Macron and his far-right challenger Marine Le Pen on April 24, an internal consultation showed.
Macron won the presidency in 2017 after easily beating Le Pen when voters rallied behind him in the run-off to keep her far-right party out of power.
Last Sunday's initial vote set up the same second-round battle, but Macron is facing a much tougher challenge with both sides desperate to court those who backed Mélenchon, who narrowly missed out on the run-off after winning about 22% of the vote.
Mélenchon has called on his supporters not to vote for Le Pen, repeating the injunction four times in a speech to supporters after the first round. But he has stopped short of advocating Macron and said his La France insoumise (France Unbowed) party would hold a public consultation to help guide those who backed him.
According to results published on Sunday from about 215,000 people who took part, more than 66% said they would abstain, leave their ballot paper blank or spoil it. Just over 33% said they would vote for Macron. The option of voting for Le Pen was not given to respondents.
"The results are not an order to vote for anybody (...). Voters will make their own choice and vote as they see fit," Mélenchon's campaign team wrote on its website.
For decades, a "republican front" of voters of all stripes rallying behind a mainstream candidate has helped to keep the far right out of power.
But Macron, whose sometimes abrasive style and policies that veered to the right have upset many voters, can no longer automatically count on that backing.
An IPSOS-Sopra-Steria poll on Saturday showed that some 33% of Mélenchon voters would back Macron with 16% supporting Le Pen on April 24. But more than 50% of people questioned declined to give their view.
With the electorate fragmented and undecided, the election will likely be won by the candidate who can reach beyond his or her camp to convince voters that the other option would be far worse.
Macron borrowed directly from Mélenchon's platform on Saturday by promising to put his next prime minister in charge of "planification écologique" (ecological planning) – a concept popularised by Mélenchon.
Addressing hundreds of supporters in central Marseille, Macron promised a "complete renewal" of his policies. He said he would also appoint a minister of "energy planning" with "a mission to make France the first leading nation to end oil, gas and coal consumption".
(FRANCE 24 with REUTERS)