Analysts say Macron has been improving his performance since a final and harsh televised debate between the two contenders on Wednesday evening, in which he was more convincing to French viewers, according to surveys.

Unlike the 2012 election, which was a race between candidates from France's right and left parties which had dominated the country's political mainstream for decades, this year, two anti-establishment candidates emerged as the frontrunners in the first round.

Macron, never held an elected office, aims to build a democratic front involving faithfuls from different political views, as well as new, talented faces.

A pro-market advocate, the 39-year-old ex-investment banker has been campaigning for a stronger eurozone and further economic openness to bolster domestic economy and create wider business opportunities for millions of people without work.

His rival, Le Pen proposed the other face of the coin via a nationalist project aiming to install internal borders to slash immigration which she considers the main cause of rising security risks and rampant unemployment.

The 48-year-old lawyer from the far-right party National Front (FN) also proposed to restore national security and to put a France exit from the eurozone to a referendum.

After a campaign overshadowed by a series of twists, the 2017 French election is one of the most unpredictable in the country's modern history, as growing public disenchantment forced many voters to turn their backs on the mainstream parties or even refuse make a choice.

An Odoxa survey released on Friday said a quarter of the French was likely to abstain in Sunday's vote, making the predicted abstention rate second-highest for a presidential election runoff since 1965.

The pollster estimates a turnout at 75 percent, compared with 77.8 percent in the first round.

"Traditionally, the turnout is higher in the second round, but this year's election does not follow the usual rules," the polling firm said.