(AFP) - French Prime Minister Elisabeth Borne resigned on Monday as President Emmanuel Macron prepared to unveil a long-awaited cabinet reshuffle in a bid to give new momentum to the final three years of his presidency.

After days of intense behind-the-scenes manoeuvring, Education Minister Gabriel Attal, 34, was emerging as the favourite to succeed Borne.

If appointed, Attal would be France's youngest ever and first openly gay prime minister.

"Ms Elisabeth Borne today submitted the resignation of the government to the president, who accepted it," the presidency said in a statement.

It emphasised that she and other ministers would continue to handle daily business until a new government is named.

But Borne's resignation letter to Macron, a copy of which was seen by AFP, hinted that she would have preferred to stay in her job.

"While I must present the resignation of my government, I wanted to tell you how passionate I was about this mission," she wrote.

While some expected a new prime minister to be swiftly named during the evening, a source close to Macron said the announcement would come only on Tuesday morning.

It was not immediately clear if this was due to a deliberately slow choreography by the presidency or last-minute objections from heavyweight government figures over the possible naming of Attal.

- 'Exemplary service' -

Commentators see the reshuffle as essential to relaunch Macron's centrist presidency for its last three years and prevent him becoming a "lame duck" leader after a series of crises.

Since he defeated the far right to win a second term in 2022, Macron has faced protests over unpopular pension reforms, the loss of his overall majority in parliamentary elections and controversy over immigration legislation.

Borne, 62, the second woman to lead the French government, has weathered these problems but never dispelled doubts about her future.

Writing on X, Macron thanked her for "work in the service of our nation that has been exemplary every day".

Other than Attal, possible candidates to succeed Borne include 37-year-old Defence Minister Sebastien Lecornu and 43-year-old Julien Denormandie, a former agriculture minister.

But a source close to the government said that Attal was now the favourite to succeed Borne.

Under the French system, the president sets general policies and the prime minister is responsible for day-to-day government management, meaning the latter often pays the price when an administration runs into turbulence.

- 'All options' -

While Macron cannot run again in 2027 presidential elections, relaunching his government is seen as crucial to help prevent far-right figurehead Marine Le Pen becoming president.

European Parliament elections in June will also pose a major test, with Macron's Renaissance party risking embarrassment at the hands of Le Pen's National Rally (RN).

Despite his age, Attal is a more political figure than the technocratic Borne, and polls have shown him to be one of the most popular government ministers.

If named, he would go toe-to-toe ahead of the European elections with another rising star of French politics, the even younger Jordan Bardella, just 28, who is now party leader of the far-right RN.

Other key posts are also subject to uncertainty in particular that of Interior Minister Gerald Darmanin, 41, a right-winger who spearheaded the immigration reform but burned his fingers when it was initially rejected by parliament.

The future of Foreign Minister Catherine Colonna and long-serving Finance Minister Bruno Le Maire was also uncertain.

Macron likes "keeping all options open until the last moment", a source close to the Elysee said.

The new premier will be the fourth prime minister since 2017 under Macron, who is accused by critics of micro-managing and centralising power in the Elysee.

"I have a scoop for you. I know the name of the (new) prime minister," left-wing politician Raphael Glucksmann joked on France 2 television.

"It's Emmanuel Macron! And the foreign minister will also be Emmanuel Macron, as will the defence minister and the culture minister."

© Agence France-Presse