French election: Macron warns of 'civil war' under Le Pen

French presidential candidate Emmanuel Macron has warned there will be "civil war" if his far-right opponent Marine Le Pen is elected.

In a TV debate before France goes to the polls on Sunday, both contenders sought to land damaging blows that highlighted their polar opposite visions for the country.

Le Pen painted the former banker and economy minister as a servant of big business and finance, and declared herself "the candidate of the people, of the France that we love."

Saying that Islamic extremists must be "eradicated" in the wake of repeated attacks since 2015, Le Pen charged that Macron wouldn't be up to the task.

Macron countered that Le Pen's anti-terror plans would play into the hands of the extremists and divide France.

He added: "This is what the terrorists expect. It's civil war, it's division, it's heinous speech."

It is the first time in France that neither candidate is from a mainstream party. Credit: AP

Branding Le Pen the "the high priestess of fear", Macron went on to paint his opponent as an empty shell, shaky on details and seeking to profit politically from the anger of French voters a dominant theme of the campaign.

"You lie all the time," he said. "You propose nothing."

Sitting opposite one another at a round table, the debate quickly became a shouting match, with no common ground between the pro-European Union centrist candidate and the anti-EU Le Pen.

They clashed over France's finances, its future and their respective proposals for tackling its ills.

They also clashed over foreign policy, with Le Pen saying Macron would be in the pocket of German Chancellor Angela Merkel.

"Either way France will be led by a woman; either me or Madame Merkel," she said derisively.

France goes to the polls to elect its next president on Sunday. Credit: PA

The first round of voting on April 23 eliminated mainstream parties from the left and right and propelled Macron, 39, who has no major party backing, and 48-year-old Le Pen into the winner-takes-all run-off on Sunday.

Macron, a former investment banker and economy minister for outgoing Socialist President Francois Hollande, is running his first-ever campaign for elected office, with a year-old grassroots movement.

Le Pen finished third in the last presidential election in 2012.

It is the first time neither candidate in the run-off is not from a mainstream party.