After weeks of twists and turns, the unpredictable race has narrowed dramatically, with surveys suggesting four candidates are in contention to win one of the top two spots in the April 23 vote and progress to the run-off election a fortnight later, AFP reported.
Scandal-hit conservative Francois Fillon and radical leftist Jean-Luc Melenchon are steaming up behind the two frontrunners, and with around one in three of the French electorate still undecided, candidates are scrapping for every vote.
Le Pen and Macron, who have both scored as high as 25 percent in voter surveys, stood at 22 percent in the latest IPSOS poll, while Melenchon has surged to 20 percent and Fillon stands at 19.
Melenchon's late surge – and the possibility he could square off against Le Pen in the May 7 decider – has sparked alarm over the future of the EU, as both candidates advocate withdrawing from the bloc for different reasons.
Outgoing President Francois Hollande weighed in on Saturday, saying Europe has "protected us against war" in the decades since World War II.
"Let us preserve it instead of scapegoating it," he said at a World War I centenary event in northern France.
Macron plans his biggest rally yet at the Bercy sports and concert hall, a venue with a capacity of 20,000.
The 39-year-old former Rothschild banker quit the Socialist government last year to form his "En Marche" ("On the Move") party and launch his bid for power as a candidate "neither of the left nor of the right".
Demonstrations against Le Pen
According to AP, hundreds of demonstrators in France marched on Sunday to protest the far-right National Front leader Le Pen, saying that basic freedoms would disappear if she were elected.
Some protesters threw firebombs at police during the march from suburban Aubervilliers to a Paris neighborhood where Le Pen was scheduled to hold a rally on Monday. Officers responded with tear gas during the small skirmishes.
A banner at the front of the march read "Paris-Suburbs Against the National Front. Marchers handed out tracts denouncing xenophobia and racism that they allege Le Pen and her anti-immigration party represent.
A protest is also expected in the southern port of Marseille on Wednesday where Le Pen plans another large rally.
Far-left candidate Jean-Luc Melenchon drew tens of thousands to a rally on Sunday, aiming to maintain momentum that has pushed the one-time outsider into contention in the French presidential election, with the first round of voting a week away, Reuters reported.
Opinion polls show the top four candidates - centrist Emmanuel Macron, far-right leader Marine Le Pen, conservative Francois Fillon and Melenchon - within touching distance of each other before the April 23 first round after a surge by Melenchon in the last few weeks.