Prime Minister Sebastien Lecornu will address parliament on Tuesday to spell out his budget priorities, hoping to win over enough Socialists to stave off losing a no-confidence vote that would plunge France further into the political mire.
The far left and far right have already filed their own no-confidence motions which will be voted on on Thursday morning. Lecornu will lose unless he can convince the Socialists to opt out of supporting the measure.
France is in the midst of its worst political crisis in decades as a succession of minority governments seek to push deficit-reducing budgets through a truculent legislature split into three distinct ideological blocs.
FIRST MEETING OF NEW CABINET
The 39-year-old was already France's shortest-serving prime minister in modern times before he retook the job late last week after resigning, but now faces the prospect of losing the no-confidence vote.
Should Lecornu fall this week, experts believe President Emmanuel Macron would have little choice but to call fresh legislative elections.
Macron has burned through five prime ministers in less than two years. He has so far refused to call fresh legislative elections or resign.
Ahead of his speech, due to start at 1300 GMT, Lecornu will head to his first cabinet meeting with Macron since he was reappointed late on Friday. Lecornu's new cabinet, in which many of the choice jobs remained unchanged from his previous line-up that lasted just 14 hours, was unveiled on Sunday night.
The Socialists, who are themselves split between centrist and harder-left factions, are meeting on Tuesday to decide whether to topple the government. Only around 25 Socialist lawmakers would need to support a no-confidence measure for Lecornu to fall.
The Socialists want Lecornu to repeal Macron's pension reform and roll out a billionaires' tax, but doing so could lead conservatives to pull their support and bring him down.
"The Socialists' collective position will depend on whether the prime minister gives up on major, significant points, in particular regarding the pension reform, but not only that. It will also depend on what he says about fiscal justice," party spokesman Arthur Delaporte said on Sud Radio.
Lecornu aims to put a more than 30 billion euro ($35 billion) squeeze on the budget next year to get the fiscal deficit down to 4.7% of economic output, La Tribune reported late on Monday.
