PARIS (AFP) ― With just over a month to go Friday before the first round of France’s presidential vote, right-wing incumbent Nicolas Sarkozy is closing the gap with Socialist frontrunner Francois Hollande.

As polls showed Sarkozy cutting his rival’s lead after several weeks of campaigning and a swerve to the right, Hollande was also facing a new threat on his left flank from firebrand Left Front candidate Jean-Luc Melenchon.

The campaign moved into a new phase Friday after a deadline passed for would-be candidates to hand in the 500 signatures from local mayors and other elected officials that they need to be registered to run.

The key players were all expected to reach the target but some fringe candidates, including conservative former prime minister Dominique de Villepin, failed to make the cut.

The signatures are to be verified over the weekend and the official list of candidates is to be published Monday.

Keen to regain momentum, Hollande has made a series of promises aimed at cementing his left-wing credentials.

“I have a vision of France founded on equality, which does not distinguish between people, where all citizens can play a full role and where no one is set aside,” he said in a speech in the northeastern city of Strasbourg.

He announced a series of measures aimed at helping poor French suburbs, including obligatory placements for trainee doctors in suburban areas and tax breaks for businesses that hire suburban youth.

Hollande also promised to create a “ministry for regional equality”, to peg fees for public transport to incomes and to boost taxes on vacant properties.

On Thursday, during a three-hour appearance on France 2 public television, he also vowed to boost taxes on the rich and to not back down on his plan for a 75 percent tax rate on incomes above one million euros.

Sarkozy, an experienced and aggressive campaigner, has stepped up his attacks and moved to consolidate his hold on the right with vows to be tough on immigration and threats to pull France from Europe’s visa-free zone.

An opinion poll this week for the first time showed Sarkozy pulling slightly ahead of Hollande and the latest survey, an Opinion Way-Fiducial study released Friday, showed them equal with 27.5 percent support in the first round to be held on April 22. The same poll showed Hollande still winning the second round on May 6 with 55 percent.

Campaigning in the city of Meaux near Paris, Sarkozy rallied a crowd of 2,000 supporters Friday, casting the Socialists as an out-of-touch elite and urging the “silent majority” to back his campaign.

“In the two months that remain, the victory, the result, will depend on you, as never before in the political history of our country,” he said.

Hollande is also facing a new challenge from Melenchon, who represents a left-wing coalition including the Communists and has enjoyed a recent bump in the polls.

Melenchon surpassed the symbolic 10 percent mark in polls last week with virulent attacks on the financial world and European austerity policies.

The Left Front is expected to pick up more momentum from a major campaign rally on Sunday, with tens of thousands set to take to the streets of Paris in support of Melenchon.

Sarkozy meanwhile may get a slight boost Friday from the withdrawal from the race of Villepin, a right-wing rival who said he had not been able to obtain the 500 signatures required to run.

Villepin, a suave diplomat best remembered for leading the charge against the Iraq war at the United Nations in 2003, had hoped to draw some right-wing support away from long-time rival Sarkozy.

But he proved to be a non-factor in the campaign, with recent polls showing him with less than one percent of public support.

Hollande’s team said Friday that it had collected between 4,500 and 5,000 signatures for his campaign.