In a heated exchange the the frontrunners turned their attention to the burkini and secularism in France.
Beaches along the south coast of France sparked controversy last summer following a series of bans on the item worn in the sea.
The leader of the Front National Marine Le Pen said: “I know you Mr Macron are in favour of the burkini on the beach.”
But the centrist Emmanuel Macron fired back as the competition between the pair intensified.
Madame Le Pen don’t put words in my mouth. I don’t need the talent of a ventriloquist. When I have something to say, I will say so myself
He said: “No, Madame Le Pen don’t put words in my mouth. I don’t need the talent of a ventriloquist. When I have something to say, I will say so myself.”
Determined not to drop the topic, Ms Le Pen: “So what do you think of the burkini?”
Mr Macron said: “My views on the burkini have nothing to do with secularism, it is to do with public order. I want to avoid any troubles to public order to divide society.
“The trap in which you have fallen is to divide our society.
Emmanuel Macron and Marine Le Pen clashed over the burkini
“Over four million French people whose religion is Islam, and most of whom are not in favour of communitarianism, you want to turn them into enemies of the Republic.
“The burkini is a problem. Some mayors have made local laws and regulation. It is a problem of public order. When public order has been disturbed the mayor is responsible and he is allowed under control of admin mag to make certain rules. Don’t defy the French on this.”
Ms Le Pen, who has been leading opinion polls to win the first run off in the French presidential election next month, fired back.
She said: “I hear people talking about liberty and we have these young women who cannot dress the way they would like to. They are forced to wear an Islamic veil simply because we have allowed Islamic fundamentalists to take over.”
Emmanuel Macron accused Ms Le Pen of putting words in his mouth
Ms Le Pen hit back against Mr Macron
But Mr Macron, who is expected to beat Ms Le Pen in the second run off, was determined to have the last word and accused the nationalist of “twisting the truth”.
The frontrunners continued to lock horns after Ms Le Pen said many French voters are not represented.
She said: “There is something no-one has mentioned perhaps because they are closely involved, it is when people benefit from the system, they go through the best elite schools and then they become a banker and then they go into politics.”
Mr Macron, a 39-year-old former economy minister and investment banker who has never run for elected office, took offence.
He said: “I feel she is aiming that me. You would be bored if I was not here.
Who will be the next President of France? Mon, March 20, 2017
Candidates for the 2017 French Presidential Election revealed
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“Don’t worry I will continue to irritate you.”
The televised three-hour debate is the first between the five main candidates.
Opinion polls show almost 40 percent of voters are not sure who to back in the election, which will be held over two rounds on April 23 and May 7 against a backdrop of high unemployment and sluggish growth.
Polls show Mr Macron and Ms Le Pen establishing a clear lead in terms of voting intentions in the first round, while Francois Fillon, the one-time front-runner who has been damaged by a financial scandal, has slipped back.
Only the top two candidates go through to the runoff, where polls see Mr Macron easily beating Ms Le Pen.
But many are still undecided and opinion polls show the abstention rate could be higher than ever in France, adding to the uncertainty.