Polls for the first round currently show centrist Emmanuel Macron and Marine Le Pen neck-and-neck.
Here is a snapshot of what happened in the race:
Jean-Luc Melenchon, predicted by polls to beat Socialist candidate Benoit Hamon as the top choice of the left, said the French no longer found him frightening.
"Today's society does not want sound and fury," the veteran rebel, known for his confrontational style and fiery speeches, told Le Journal du Dimanche (JDD) weekly.
"I'm becoming a reassuring figure," said 65-year-old Melenchon, adding: "I'm less of a hothead."
Melenchon wants to abolish France's "monarchical" presidency and introduce reforms that give more power to parliament.
Polls for the first round currently show centrist Emmanuel Macron and Le Pen neck-and-neck, followed by the conservative Francois Fillon in third, Melenchon in fourth and Hamon in fifth.
Macron is tipped for victory over Le Pen if the pair compete in May's run-off.
At a rally in the western city of Bordeaux the National Front (FN) leader came out swinging against Macron's plans for positive discrimination policies in poor, predominantly immigrant neighbourhoods.
"Macron's positive discrimination means negative discrimination for others in their own country," said Le Pen, who has pledged a French-first approach to public housing, jobs and benefits.
With surveys forecasting a record abstention rate over 30 percent, she urged young people -- shown as least likely to cast a ballot -- to have their say.
"Vote, I beg you. Don't let yourselves be turned off by those who despise candidates that were not anointed by the system," Le Pen said.
Her remark was seen as a swipe at Macron, who on Saturday called on the French to "drive out... the party of hate" -- a reference to the FN.
The deputy leader of the Republicans party, Laurent Wauquiez, urged rightwing voters to overcome any reservations they may have about Fillon and cast their ballot for the scandal-hit conservative.
"I'm calling for a tactical vote on the right and centre. You want to turn the page after five years of (Socialist President Francois) Hollande? Then vote Fillon, whatever you think about the scandals," Wauquiez told Le Journal du Dimanche.
Fillon's campaign was thrown into flux by revelations that he paid his wife and two of his children nearly a million euros in total for suspected fake jobs as parliamentary assistants.
He was also revealed to have accepted gifts of luxury suits from a wealthy benefactor. He has since returned the suits.