The election delivered a hung parliament, with Macron now having to pick a prime minister who can please three similar-sized political blocs - the left, the far right and his centrist grouping - with little inclination to make concessions.

Macron has been meeting with political leaders from across the political spectrum to identify a possible prime minister for weeks, but to little avail. With his hand irrevocably weakened by the election result, he has been left with little choice but to weigh concessions on his hard-won pension reform detested by the left or forswear tax hikes as demanded by conservatives.

"The president is taking his time because he doesn't want a prime minister who will touch his economic legacy. Tax hikes and retirement reform are his red lines," Socialist lawmaker Arthur Delaporte told Reuters.

Rivals are loathe to be seen cutting any favours to Macron, who is deeply unpopular on the left and right alike.

His bargaining position weakened further on Tuesday after Edouard Philippe, his popular former prime minister, chose to capitalise on the void, announcing his candidacy in the next presidential election in 2027.

Despite his unpredictability, Macron is unlikely to heed calls from the left to resign. Still, Philippe's move, coupled with the difficulty of the president's predicament, raises questions about whether Macron will see out his second and final term.

Delaporte called Philippe's move "a stab in the president's back," while Conservative Senator Bruno Retailleau suggested the Macron era was now drawing to a close.

"We've entered a new period," he told BFM TV.

WEEKS OF TALKS

Sources close to Macron said that after weeks of consultations, Macron had narrowed contenders for prime minister down to ex-Socialist Prime Minister Bernard Cazeneuve from the left and former labour minister and Hauts-de-France regional head Xavier Bertrand for the conservatives.

It is unclear if either of them could win enough parliamentary support to form a government, or face immediate no-confidnce votes that would humble Macron and bring France back to square one.

Senator Laure Darcos, a Bertrand ally, told Reuters he would not try to dismantle Macron's 2023 retirement reform, which led to weeks of street protests and was only passed by bypassing parliament.

While the left and far right are dead set on rolling it back, even Macron's centrist ally and political veteran Francois Bayrou has said the president should consider tweaks to water it down.

As Macron's hunt for a prime minister has dragged on, public finances have fast deteriorated and outgoing Finance Minister Bruno Le Maire says tens of billions of euros in budget cuts are needed to plug the hole.

But left-wing lawmakers demand broad-based tax hikes instead, which is scarcely palatable for Macron after he cut taxes on companies and households by over 50 billion euros since he first took office in 2017.

Conservative lawmaker Veronique Louwagie told Reuters that her Republicans party could not back a prime minister who would raise taxes or allow the public finances to spiral out of control.

Whoever Macron picks will face a baptism of fire as time is running out to prepare 2025 budget legislation, which could trigger a separate vote of no confidence if other parties are not satisfied.

Should that happen, "I don't see any other solution than Macron's resignation," said left-wing lawmaker Eric Coquerel. "When things are blocked, something's got to give."