It’s the best of times for Notre Dame, but the worst of times for the French PM | Angelique Chrisafis in Paris

When Emmanuel Macron welcomes world leaders to the reopening of Paris’s Notre Dame Cathedral this weekend, after fire damaged it five years ago, he might have hoped it would serve as a metaphor for people from all backgrounds coming together to prevent a hallowed edifice collapsing.

Instead, it is likely the French government itself will have fallen by Wednesday evening, with voters’ trust of politicians and the political process in charred ruins.

The French president is entering a new period of political uncertainty and parliamentary chaos, which critics say is of his own making. The repercussions are still being felt from his gamble of calling a snap parliamentary election in June.

It was never going to be easy when the rightwing former Brexit negotiator Michel Barnier was appointed by Macron as prime minister in September, after a summer of political paralysis in the wake of an inconclusive election.

But it has taken only three months for Barnier to face being ousted in a no-confidence vote, likely to become the shortest-lived premier in modern French history.

The political landscape in France remains more deeply divided than ever. The snap election saw a leftwing coalition become the biggest political force after tactical voting held back the rise of Marine Le Pen’s far-right anti-immigration National Rally party (RN).

But instead of appointing a prime minister from the left, which fell short of an absolute majority of 289 seats in the national assembly, Macron hesitated for months then opted for Barnier, whose traditional rightwing party Les Républicains had come a lowly fourth in the vote – behind Macron’s damaged but still-standing centrist grouping, and far behind Le Pen’s party.

The left called it a denial of democracy. Le Pen, whom many voters on the left and centre had clubbed together to keep from power, was now essentially propping up Barnier’s minority coalition in an unprecedentedly powerful role.

Barnier, in order for his government to last, had to keep Le Pen neutralised to prevent her from joining the leftwing opposition in a no-confidence vote. He was so keen to show favour to the RN leader that he personally called her in September to calm and reassure her when his economy minister, Antoine Armand, spoke publicly about not wanting to work with MPs from the far right. In recent days, when Le Pen voiced her “red lines” over Barnier’s budget plans, he made very public concessions – from electricity taxes to prescription medication costs – until the final hour. But this failed.

The leftwing daily Libération said Barnier had “grovelled” to Le Pen. Le Pen and her party in effect pulled the plug, saying they would vote for the left alliance’s no-confidence motion on Wednesday night, which will bring Barnier and the government down.

Le Pen’s political tactics and ambition appear to have been underestimated by Barnier and his team. Perhaps Barnier’s experience of negotiating Brexit with the British, awkward as it often was, was no match for the bitter rivalry of French politics at home.

Le Pen, for now, emerges strengthened. Thanks to Barnier, her anti-immigration party – which for decades was regarded as a danger to democracy that promoted racist, antisemitic and anti-Muslim views and had to be kept out of mainstream politics at all costs – has, for the first time in its 50-year history, been openly negotiated with by a government and treated on a level playing field.

The National Rally knows many of its voters are struggling with the cost of living. It said it was opposing Barnier’s social security budget and belt-tightening plans to protect its almost 11 million voters. Le Pen’s supporters in constituencies across France were also increasingly angry at Macron and keen for the National Rally to act against the government.

Barnier’s team had thought Le Pen would never oust them because she instead wanted to present herself as a source of stability in parliament rather than plunging France into crisis with a government collapse.

But as well as pressure from far-right voters, Le Pen was facing her own legal problems, which had increased the urgency for her to act. Widely seen as the frontrunner in the 2027 presidential race, she faces the possibility of being barred from running in that election after prosecutors sought a mandatory five-year ban from public office for her alleged role in embezzling EU parliament funds to pay staff in France. She denies the allegations. A verdict and sentence will be handed down by judges in March 2025.

Macron himself is under no obligation to resign over the political chaos and has previously said he won’t. The president’s final term ends in 2027.

There cannot be another parliament election until July 2025 at the earliest. So, if the government falls, Macron must appoint another prime minister to form a new government to work with the same divided parliament. There is political uncertainty over how a budget will be decided.

Barnier had promised a “new era” for France when he was appointed. This week, he warned the no-confidence vote was “plunging France into the unknown”.