France’s centrist presidential contender Emmanuel Macron has singled out the far-right National Front as his chief rival, vowing to win the first round on April 23 as a new poll showed the election race getting tighter.

“The National Front, our main opponent, is attacking us on all sides. Never boo them. Fight them,” a defiant Macron told a rally in Marseilles.

“I want us to kick far from this campaign and from the country the party of hatred and contempt and all those who make us so ashamed. We are going to be ahead in the first round and we’re going to beat them,” he said.

The presidential race is even closer than it was a week ago, an opinion poll indicated on Saturday.

First-round voting intentions for the frontrunners, Macron and National Front leader Marine Le Pen, showed both slipping one percentage point to 25 per cent and 24 per cent respectively.

Third-placed conservative Francois Fillon gained two points to 19 per cent, while the far left’s Jean-Luc Melenchon climbed one point to 15 per cent, according to the survey by the BVA polling institute.

The poll though, like others this year, showed Macron beating her with 60 per cent of votes in the May 7 second round.

During his visit to Marseille, Macron met conservative and security hardliner Christian Estrosi, part of his strategy to show he wants to transcend the right-left divide.

– AAP