"I am once again standing as a presidential candidate, before you," Le Pen, who heads up the far-right Rassemblement National party, told a news conference.
Nevertheless, concerns about his government's handling of the COVID-19 pandemic, and worries about terrorism, immigration and violent crime, have dented Macron's standing.
Macron and Le Pen would easily qualify for the runoff after picking up about 25% each in the first round scheduled for April 2022, far ahead of other rivals. Macron would go on to defeat Le Pen with 53% of the votes versus 47%.
"Centre-left voters are disappointed, that's for sure," one minister, speaking on condition of anonymity, told Reuters.
The election of Marine Le Pen , we all know that is a possibility. It is a political possibility and it must be opposed...I hope that Emmanuel Macron runs and is re-elected.
Opinion polls indicate she will be Macron's main challenger in the election next year.