France's presidential candidates traded fresh blows yesterday after one of the fiercest TV debates in the nation's history, with frontrunner Emmanuel Macron holding on to his status as favourite for the weekend's decisive run-off.

The centrist Macron and his far-right rival Marine Le Pen clashed repeatedly over terrorism, the economy and Europe in Wednesday's hot-tempered debate watched by 16.5 million people.

Le Pen branded the 39-year-old former economy minister and investment banker "the candidate of the elite" while he called her "the high priestess of fear".

After the bruising contest, a snap poll by French broadcaster BFMTV found that 63 percent of viewers thought Macron was the "most convincing" of the two, broadly mirroring forecasts for the decisive election on Sunday.

Former US president Barack Obama threw his support behind the pro-EU Macron, dubbing him as a "liberal"

candidate.

The rivals were at each other's throats again on Thursday, with Le Pen defending the aggressive tone of the debate by arguing that she had tried to "lift the veil... on who Mister Macron is" and he again accused her of lying constantly.

Macron told France Inter radio: "You can't choke off all of the lies but

you can kill off some of them."

He filed a legal complaint after Le Pen implied during the debate that he had an " offshore account in the Bahamas".

With just two days of campaigning left, Le Pen received a rowdy welcome in the Brittany town of Dol-de-Bretagne, where protesters threw eggs at her entourage, although she was not hit.

Macron headed to the southwestern town of Albi to meet supporters.

The aggressive and often unruly debate shocked many observers. Le Monde said it had been "brutal" and "violent from start to finish".

The debate was probably Le Pen's last chance to change the dynamics of the race ahead of the final weekend of a long and unpredictable campaign.

But the poll by Elabe for BFMTV showing that Macron had convinced 63 percent of viewers compared to 34 percent for Le Pen suggests she did little to win over new support.

Macron would win around 60 percent to Le Pen's 40 percent if the vote were held now, surveys suggest.