The champagne had been laid out along with the “petits fours” and Marine Le Pen’s troops were in buoyant mood at National Rally campaign headquarters in Paris after a first round of snap elections in which they came out way in front.

Polls had suggested for the past week that they would repeat the performance in Sunday’s run-off, perhaps winning an outright majority of 289 out of 577 seats and crowning 28-year-old Jordan Bardella prime minister.

Such an outcome would leave French president Emmanuel Macron a lame duck for his remaining three years in office and see him challenged in his only remaining roles: foreign and defence policy.

“We’ll either get an absolute majority or be a few seats off,” one young recruit, a law student who joined the party to rein in “rampant immigration” and rising living costs, confidently predicted.

But by 8pm local time, the champagne fizzled out and boos erupted around the room as shock initial results beamed onto blue screens. 

National Rally had been beaten by a ragtag alliance called the New Popular Front - comprising Jean-Luc Mélenchon’s hard-Left France Unbowed, Communists, Greens and Socialists.

But even more humiliatingly Le Pen’s party appeared to have been beaten by Mr Macron’s centrist Together alliance, which polls had predicted would founder in third place.

“This is not what we were expecting to see,” said Julien Durand, 45, who put his head in his hands as the announcements came on French television. “Clearly people are still afraid of the old stereotypes about the far-Right, which are no longer relevant.”

Meanwhile, cries of joy and tears of relief broke out at the Leftist alliance’s gathering in Paris when the estimates were announced with people spontaneously hugging strangers and several minutes of non-stop applause after the projections landed. 

At the Greens’ headquarters activists screamed in joy, embracing each other.

“I’m relieved. As a French-Moroccan, a doctor, an ecologist activist, what the far-Right was proposing to do as a government was craziness,” said 34-year-old Hafsah Hachad.

As for Mr Macron, they called him the sorcerer’s apprentice, even “unhinged”, but the French president’s decision to dissolve parliament and call snap elections appears to have partially paid off.

The first round of these legislative elections amounted to a referendum for or against Mr Macron. 

The French electorate clearly came out against the president. The second round was framed as a referendum for or against the National Rally, and the French clearly came out against handing power to the hard Right.

The result was helped along by some canny politicking, with deals done to withdraw candidates so Le Pen politicians could be defeated by a messy coalition of voters.

True, the result still amounts to historic gains for the Le Pen camp but there is no doubt that they also constitute a slap in the face for the RN and its slick young “TikTok king”, Mr Bardella, who walked the walk but failed to impress when it came to credible policy.

The result could also seriously put the brakes on Ms Le Pen’s ambitions to be president in 2027. On Sunday night, she claimed her victory was merely “deferred”, stressing that RN was “the leading” party in France.

“The tide is rising. It didn’t rise high enough this time, but it continues to rise and, as a result, our victory is only delayed,” she said on French television, adding: “I have too much experience to be disappointed by a result where we double our number of MPs.”

However, her seemingly inexorable rise has lost key momentum.

The main victor is what has been called the “Republican front”, namely all those French who chose to vote tactically in 200-odd constituents to keep the RN out.

As Alain Duhamel, the respected political analyst put it: “This the most spectacular surprise in modern French politics by a mile.”

Undeniably, Mr Macron has also been sorely chastened, with his Ensemble group losing around 100 seats in the space of two years. But it will remain a force to be reckoned with in the national assembly.

The question now is who will join forces to form a coalition government and who will be prime minister?

Gabriel Attal, his 35-year old head-of-government who ran his campaign, last night offered his resignation.

In a message after the result, Mr Macron’s office said that the president would “wait for the new national assembly to organise itself” before making any decisions.

The Macron camp and Mr Mélenchon’s LFI party have already ruled out joining forces. Indeed, Mr Mélenchon called on the president to step down last night.

Meanwhile, the Left may have been united during the campaign but have displayed huge differences in the past; a similar alliance of parties fell apart over the Israel-Gaza war and has also divided over Nato and the war in Ukraine.

Crucially, power will now move away from the Elysée Palace to the French parliament as Mr Macron enters a period of “co-habitation”. Mr Macron who theorised his role as Jupiter, the Roman God of Gods, now finds himself confined to a far lesser role, in charge or foreign and defence affairs.

Meanwhile, often dubbed “door mats” when the president has a parliamentary majority, French MPs will now call the shots and several heavyweight politicians will enter parliament, including socialist ex-prime minister Francois Hollande.

Raphaël Glucksmann, a leading Left-winger whose socialist-backed list came third in European elections, said that France is having to make political compromises via coalitions in parliament, much like in Italy or Germany.

“We’re in the lead, but we’re in a divided assembly and so we’re going to have to behave like adults.”

As Mr Attal, the outgoing prime minister, put it: “Tonight, no absolute majority can be driven by the extreme. And this is because of the French spirit.”

As for Mr Macron, on Wednesday he travels to Washington for the Nato summit, and the waiting congratulations of his fellow leaders.