The debate will be broadcast nationwide on two TV channels, according to the source.
The debate will be broadcast nationwide on two TV channels, a source said.
Macron first sought a debate with Le Pen in February "which she refused. Now we are going to have one," the source added.
Le Pen's campaign director, David Rachline, earlier said that the debate "should take place," as it would help the public "to see with great clarity the two choices of society which are being put forward".
Macron, a 39-year-old political novice and former banker, headed the pack in the first round of voting on Sunday, picking up 23.75 percent of the vote.
He will face off with Le Pen, 48-year-old head of the far-right National Front, who won 21.53 percent.
The other candidates, including those from the traditional mainstream left and right parties, were eliminated.
Macron is campaigning on a centrist platform that favours business, the European Union and maintaining France's welfare safety net.
Le Pen is campaigning on a nationalist platform that would curb immigration and weaken ties with the European Union.