Earlier, Alexander Navalny, the jailed Russian dissident, had accused Ms Le Pen of entering a corrupt “influence peddling” pact with Mr Putin in exchange for a €9 million (£7.5 million) loan she has not fully repaid from a bank he called “Putin’s notorious money-laundering outfit”.

Mr Macron returned to the issue, saying: “You are not speaking to other leaders when you speak to Russia, you are speaking to your banker.”

She insisted she had only taken out the loan because no French bank would give her one and she was paying it back.

While Mr Macron never looked on the back foot, his rival often looked flustered but did not fall apart. Her best response was when he accused her of being a “climate sceptic” for wanting to tear down wind farms. “I’m not climate sceptic,” she said. “But you’re a climate hypocrite.”

Mr Macron reiterated previous claims that Ms Le Pen’s plans for “an alliance of nations” meant she intended to “leave the EU without saying it”.

Le Pen more polished than 2017 disaster

After a bruising second-round campaign, Mr Macron holds a solid poll lead of around 10 points but his camp had warned against any complacency in the prime-time duel watched by millions.

Undecided voters and abstentions could yet swing the outcome.

An Elabe poll take just after the debate found that 59 per cent of viewers thought Mr Macron was the “more convincing” candidate with Ms Le Pen on 39 per cent. Two per cent of respondents had no opinion.

The National Rally candidate’s disastrous performance in 2017 is widely thought to have sealed her defeat but this time her camp insisted she was far better prepared after sparring with a graduate of ENA, the top school for future leaders where Mr Macron studied.