French lawmakers on Wednesday voted to oust the government of Prime Minister Michel Barnier after just three months in office, an historic move which hurled the country further into political uncertainty.

For the first time in over sixty years, the National Assembly lower house toppled the incumbent government, approving a no-confidence motion that had been proposed by the hard left but which crucially was backed by the far-right headed by Marine Le Pen.

Barnier's rapid ejection from office comes after snap parliamentary elections this summer which resulted in a hung parliament with no party having an overall majority and the far-right holding the key to the government's survival.

President Emmanuel Macron now has the unenviable choice of picking a viable successor with more than two years of his presidential term left.

He is to address the nation at 1900 GMT on Thursday, the Elysee said.

The National Assembly debated a motion brought by the hard left in a standoff over next year's austerity budget, after the prime minister on Monday forced through a social security financing bill without a vote.

With the support of the far-right, a majority of 331 MPs in the 577-member chamber voted to oust the government.

Speaker Yael Braun-Pivet confirmed Barnier would now have to "submit his resignation" to Macron and declared the session closed.

Macron flew back into Paris just ahead of the vote after wrapping up his three-day state visit to Saudi Arabia, an apparent world away from the domestic crisis.

He strolled earlier on Wednesday through the desert sands of the Al-Ula oasis, an iconic tourist project of the kingdom, marvelling at ancient landmarks. After landing, he headed direct to the Elysee Palace.

"We are now calling on Macron to go," Mathilde Panot, the head of the parliamentary faction of the hard-left France Unbowed (LFI) party told reporters, urging "early presidential elections" to solve the deepening political crisis.

But taking care not to crow over the fall of the government, Le Pen said in a television interview that her party – once a new premier is appointed – "would let them work" and help create a "budget that is acceptable for everyone."

Laurent Wauquiez, the head of right-wing deputies in parliament, said the far-right and hard-left bore the responsibility for a no-confidence vote that will "plunge the country into instability."

Macron on Tuesday had rejected calls to resign, saying such a scenario amounted to "political fiction."

With markets nervous and France bracing for public-sector strikes against the threat of cutbacks, action that will shut schools and hit air and rail traffic, there is a growing sense of crisis.

The unions have called for civil servants, including teachers and air traffic controllers, to strike on Thursday over separate cost-cutting measures proposed by their respective ministries this autumn.

Meanwhile, Macron is due to host a major international event on Saturday, with the reopening of the Notre-Dame cathedral after the 2019 fire, with guests including Donald Trump on his first foreign trip since he was elected to be the next US president. (AFP)