PARIS (REUTERS) - French President Emmanuel Macron on Friday (April 8) appealed to younger, progressive-leaning voters in his last scheduled interview before Sunday's first-round presidential vote while his forecast lead over far-right candidate Marine Le Pen further evaporated.

"When it comes to correcting social inequalities at their root, we have begun the work, but we are very far from having succeeded," he told online news outlet Brut in a long interview, pledging also to do more to fight climate change.

Less than 48 hours before the first-round vote, the race for the top job in the euro zone's second-largest economy appeared to be coming down again to the two finalists of the 2017 election.

But while Mr Macron was still slightly ahead in opinion polls, his re-election no longer appeared to be a foregone conclusion on Friday with Le Pen climbing in surveys, some of them putting her within the margin of error.

A poll on Friday showed the tightest gap ever, with Le Pen seen winning 49 per cent of votes in a likely runoff against the president, her best polling score on record.

The poll, published on BFM TV's website showed that Mr Macron had lost a further two points at 26 per cent support and Le Pen had gained two points to 25 per cent.

Hours before candidates and their aides are required by French election law to refrain from making any political statements until election offices close on Sunday evening, there was a growing sense of discomfort among Macron supporters.

"I think we'll be okay, but it's going to be a hard one," one minister, who spoke on the condition of anonymity, told Reuters.

Campaign insiders say Mr Macron urgently needs to appeal to the broadest possible voter base before the first round, because coming second behind Le Pen on Sunday would give her strong momentum ahead of the runoff.

Le Pen has centered her bid on purchasing power, softening her image and tapping into promising to cut taxes and hike some social benefits, worrying financial markets as she gains momentum in the polls.

Rival far-right candidate Eric Zemmour's radical, outspoken views have helped her look more mainstream and many left-leaning voters have told pollsters that, unlike in 2017, they would not vote in the second round to keep Le Pen out of power.

"They won't necessarily vote for Marine Le Pen, but they don't want to vote for Emmanuel Macron," said Mr Jean-David Levy, the deputy director of polling institute Harris Interactive.

"Marine Le Pen has never been so capable of winning a presidential election."

As some in the president's camp complained about a lack of preparation, his team having spent the bulk of the last months dealing with the war in Ukraine, Mr Macron on Friday voiced regrets about having joined the race much later than his competitors.

"So it is a fact that I entered (the campaign) even later than I wished," Mr Macron said, adding that he retained a "spirit of conquest rather than of defeat".

Mr Macron, who has spent the past five years wooing the centre-right, suddenly changed course, telling voters he would further shield them from rising living costs and the dangers of Ms Le Pen, whom he labelled a racist.

In his last scheduled interview before Sunday's vote, Mr Macron reiterated his warning against the rising far-right.

"They play with the fear," Macron told online news outlet Brut on Friday in a last-minute appeal to progressive-leaning, younger voters.

"They make short-term minded proposals, the financing of which sometimes is completely unclear."

According to opinion polls, around a third of voters have yet to make up their minds, which analysts say often favours candidates with realistic chances to enter the second round as undecided voters tend to go for what the French call a "useful vote", meaning voting strategically.

Other than Mr Macron and Ms Le Pen, this trend is set to favour far-left veteran Jean-Luc Melenchon who - also on an upward trend - ranks third with around 17 per cent of forecast votes.

Left-wing figure Christiane Taubira, a former minister who dropped out of the race after she failed in her attempt to rally the left behind her, on Friday endorsed Mr Melenchon, saying he was now the left's best hope.