France's new Prime Minister Sebastien Lecornu and his government resigned on Monday, hours after Lecornu announced his cabinet line-up, in a major deepening of France's political crisis that drove stocks and the euro sharply lower.

The swift, unexpected resignation came after allies and foes alike threatened to topple the new government, with Lecornu saying that meant he could not do his job.

Opposition parties immediately urged President Emmanuel Macron to resign, or call a snap parliamentary election, saying there was no other way out of the crisis.

Lecornu, who was Macron's fifth prime minister in two years, stayed in the job for only 27 days. His government lasted 14 hours, making it the shortest-lived in modern French history at a time when parliament is deeply divided and the euro zone's second-largest economy is struggling to put its finances in order.

What's next?

French politics has become increasingly unstable since Macron's re-election in 2022 for want of any party or grouping holding a parliamentary majority. Macron's decision to call a snap parliamentary election last year deepened the crisis by producing an even more fragmented parliament.

The centrist president could now call new snap elections, resign or try to appoint yet another prime minister. In past months, Macron, whose mandate runs until May 2027, has repeatedly ruled out the first two options. He is yet to react publicly to Lecornu's resignation.

BFM TV showed footage of Macron walking by the Seine, cutting a lonely figure.

Opposition wants snap elections

In the opposition, many rushed to ask for Macron to call new snap parliamentary elections or resign.

"Macron must now choose: dissolution or resignation, and fast!" the far-right National Rally (RN) said on X.

"This joke has gone on long enough, the farce must end," RN leader Marine Le Pen said.

Mathilde Panot, of the hard left France Unbowed, said: "Lecornu resigns. 3 Prime Ministers defeated in less than a year. The countdown has begun. Macron must go."

David Lisnard, of the conservative Republicans, was also among those who called on Macron to leave.

To explain why he could not go forward and strike compromises with rival parties, Lecornu blamed the "egos" of opposition politicians who rigidly stuck to their manifestos, while those inside his minority coalition were focusing on their own presidential ambitions.

"You should always prefer your country to your party," he said in a short speech after his resignation.

New cabinet line-up angered opponents

After weeks of consultations with political parties across the board, Lecornu, a close ally of Macron, had appointed his ministers on Sunday and they had been set to hold their first meeting on Monday afternoon.

But the new cabinet line-up had angered opponents and allies alike, who either found it too right-wing or not sufficiently so, raising questions on how long it could last.

Lecornu handed his resignation to Macron, who accepted it.

French stocks and euro fall

Paris' $3 trillion CAC 40 (.FCHI), opens new tab dropped more than 1.5%, making it the worst-performing index in Europe, as banking shares came under heavy fire.

The euro slid 0.7% on the day to $1.1665.

Lecornu's two predecessors, Francois Bayrou and Michel Barnier, were brought down by parliament over efforts to rein in France's public spending at a time when ratings agencies and investors are watching closely.

France's debt has risen to 113.9% of gross domestic product, while the deficit was nearly double the European Union's 3% limit last year.

"It's just one government after another... this is the major problem for French assets, but it has a spillover effect for the rest of Europe," said Chris Beauchamp, chief market analyst at IG Group.

Deep instability

France has rarely suffered a political crisis so deep since the creation in 1958 of the Fifth Republic, the current system of government.

The 1958 constitution was designed to ensure stable governance by creating a powerful and highly centralised president endowed with a strong majority in parliament, and to avoid the instability of the periods immediately before and after World War Two.

Instead, Macron - who in his ascent to power in 2017 reshaped the political landscape - has found himself struggling with a fragmented parliament where the centre no longer holds the balance and the far-right and hard-left hold sway.

France is not used to building coalitions and finding consensus.