'The money party has too many candidates in this election,' the 49-year-old former education minister declared.
French Socialist Benoit Hamon attempted to turn around his flagging presidential campaign on Sunday, attacking his main rivals as the "money" candidates in a key speech aimed at halting his poll slide.
"Everything begins today," said Hamon, 49, a leftist rebel who was the surprise winner of the party's presidential nomination in January but has struggled since to unite the party around his bid.
A poll published Sunday showed him dropping four points in two weeks, falling back into joint fourth with Communist-backed radical Jean-Luc Melenchon in the first round of the election on April 23.
The poll of 1,508 voters by Kantar Sofres credited both men with 12 percent.
It showed far-right leader Marine Le Pen and centrist candidate Emmanuel Macron neck-and-neck with 26 percent each, ahead of scandal-hit Republicans nominee Francois Fillon with 17 percent. All polls show Le Pen being beaten by Macron in the May 7 second round runoff.
Hamon, who made waves during the Socialist primary with his pledge to introduce a universal basic income and tax robots that take workers' jobs, took aim Sunday at the role of money in the race.
"The money party has too many candidates in this election," the 49-year-old former education minister declared.
"One says 'Get rich!' and the other two say 'Make us rich!'", he said, referring in the first instance to liberal ex-banker Macron and in the second to Fillon and Le Pen.
Fillon was last week charged with misuse of public funds overpayments totalling nearly one million euros to his wife and children, whom he employed as parliamentary assistants.
Le Pen, for her part, has faced allegations of illegal campaign financing and misusing European Parliament funds as well as claims that she and her father Jean-Marie Le Pen failed to declare the full value of family properties.
Macron responded Sunday by noting Hamon should spend less time attacking the competition.
"I don't waste... my time at my rallies railing against the other candidates," he said on France Television, adding money is neither something to "cherish" nor to "detest".
Hamon's impassioned speech to thousands of supporters at Bercy concert hall followed a show of force Saturday by 65-year-old Melenchon, who drew tens of thousands of people at a Paris march for a "Sixth Republic".
Melenchon wants France to scrap its "monarchical" presidential system under the 59-year-old Fifth Republic and replace it with a parliamentary system.
On Saturday, he urged voters to use their vote "to clear out" the political establishment.
A consummate campaigner, he has refused calls to join forces with Hamon to try ensure the splintered left makes it past the first round of the election.
Melenchon says he no longer trusts the Socialists after five years of business-friendly policies under current President Francois Hollande.