PARIS, March 21 (Xinhua) -- Centrist presidential candidate Emmanuel Macron was seen as the most convincing candidate among top contenders in the first televised debate on Monday, a poll showed.

Twenty percent of viewers thought Macron had dominated the marathon prime-time debate that lasted three hours and a half, with 30 percent thinking he was proposing the best project to put France on a recovery track, according to a snap Elabe survey for the BFMTV news channel.

Hard left nominee Jean Luc Melenchon was seen convincing by 20 percent, followed by Marine Le Pen, far-rightists leader, and conservative Francois Fillon with 19 percent. The Socialist Benoit Hamon trailed behind with 11 percent.

With French presidential campaign flagging and haunted by fraud probes, the top five of presidential hopefuls tried to reach out disillusioned and undecided voters to help them make up their minds five weeks before the election.

The debate, the first face-off held before the presidential election's first round, kicked off with education and social issues, with the tone among the five candidates being respectful. When it moved onto immigration and secularism, it became tonic with vitriolic exchanges between the two front-runners -- Macron and Le Pen.

The anti-immigrant contender accused her rival centrist of being in favor of the burkini, a full-covered swimsuit for Muslim women that triggered a controversy last summer.

"I do not need a ventriloquist, I assure you ... When I have something to say, I say clearly," Macron fired back.

"The trap in which you are falling, by your provocations, is to divide society," he added.

Le Pen, who hopes for a populism surge, later in the debate lashed out at her rival over his neither left nor right platform that was leading him to make an "empty" project.

"It's completely empty. I want to attract the French people's attention to the fact that every time you talk, you say a bit of this, a bit of that, and never decide," she said.

However, the pro-liberal market challenger said that proposing a project "aims to better protect you, without dividing you. It is a project that frees, giving more manoeuvre to those who want to initiate."

"The old solutions, the established order are no longer the right ones," he added.

A daily Opinionway poll on Monday showed Le Pen maintaining the lead in terms of vote intentions with 27 percent in the first round, ahead of Macron's 23 percent and Fillon's 18 percent.

For the run-off, the polls predicted Macron would comfortably beat Le Pen.

Two more televised debates, scheduled for April 4 and 20, will precede the two-round vote on April 23 and May 7.

Eleven candidates are officially competing to book a ticket to occupy the Elysee Palace in 2017 for presidency during the next five years.