His prime minister was among the last to know. That is how secretive, how confined to a small group of advisers President Emmanuel Macron’s shock decision to dissolve Parliament and call French legislative elections was.

Gabriel Attal, 35, was a personal favorite, his wunderkind, when Mr. Macron named him prime minister in January. Yet, just months after entrusting Mr. Attal with the task of revitalizing his government, Mr. Macron snubbed him as he considered one of the most important decisions of his presidency: whether to call an election at the very moment the anti-immigrant National Rally party had surged.

Mr. Macron’s style has always been intensely top-down, but this time he has played with the possibility of ushering in the once unthinkable in the form of a far-right government. The small group making the decision was so insular that even many of his ministers and supporters were left dumbfounded at his readiness to take such a gamble.

A photograph posted by Mr. Macron’s official photographer on Instagram captured the dismay when, on June 9, Mr. Macron told his government of his decision. Mr. Attal, arms crossed, looks blank. Gérald Darmanin, the longtime interior minister who has since announced he will likely leave the government, looks incredulous, his hands clasped in front of his face.

Mr. Macron, defining himself as an “incorrigible optimist,” insists he had to call the election, which would leave him as president but could force him to share power with his sworn opponents for his final three years in office. His favorite word has become the “clarification” that he says only a national vote can deliver. After his party was trounced by Marine Le Pen’s National Rally in European Parliament elections, to have carried on as if nothing had happened would have been to show contempt for democracy, he told journalists.

Still, nothing obliged him to hold a snap election, just weeks before the Paris Olympic Games, that could bring the nationalist right to power.

“He has played Russian roulette with France,” said Célia Belin, a senior policy fellow at the European Council on Foreign Relations in Paris. “It’s close to unpardonable.”

Certainly, something has shifted. Mr. Macron, who took the country by storm seven years ago when he came from nowhere to bury the old alignments of French politics and become president at the age of 39, seems increasingly isolated now in his bold — some say hubristic — certainties, surrounded by a shrinking circle of acolytes.

“‘I take you, I drop you’: That’s Macron and that’s what he did to Attal,” said Marisol Touraine, a former minister of health and social affairs who has been Mr. Attal’s political guru. “He consumes people.”

Paris chatter is alive with expressions like “wild gamble,” “lost touch with reality” and “blinding ego,” as people struggle to comprehend why their president chose to risk so much.

The reality of France today is that the National Rally, having softened its image but retained its core belief that immigrants represent a dilution of Frenchness, has proved the party most adept at tapping into widespread fears, resentments and anger at a lofty president.

Mr. Macron, twice elected and never defeated on the national stage, still believes he will triumph, and of course it is still conceivable he could. He believes that, confronted by the far right with its threat to some of the core values of the Republic and a far left whose antisemitic outbursts have shocked many people, the French will opt again for the common sense of “la Macronie,” the pragmatic politics of a right-leaning center.

In his entourage, officials who insisted on anonymity in line with French political practice, said the notion that Mr. Macron had become unpopular was a myth. They cited as evidence his appearance this month in the streets of Bayeux, a town in Normandy, where some 3,000 people turned out to greet him, far more than an expected 800.

“Plenty of people might not like Macron, but they respect him,” one official said.

It took boldness to change a country resistant to any dilution of its social model. Over seven years, Mr. Macron has slashed unemployment, made France attractive to fast-growing foreign investment, fostered a thriving start-up technology sector, fought hard to persuade the French that a retirement age of 62 is no longer reasonable, and steered the country through the Covid-19 crisis.

What Mr. Macron has been unable to do, however, is shed an image of arrogance shaped by elite schooling and remoteness from the concerns of French people who struggle to make it through the month in places far from the knowledge economy of big cities.

This failure is now accompanied by the beginnings of a fin-de-régime rush for the exits because Mr. Macron is term-limited and must leave office in 2027.

The result is clear enough. The latest Ifop-Fiducial poll this week gave Mr. Macron’s party and its allies just 21 percent of the vote in the two-round election on June 30 and July 7. The National Rally was in a comfortable lead at 36 percent, and the New Popular Front group of parties ranging from the socialists to the far left at 28.5 percent.

So acute is the perceived animosity toward him that many centrist candidates have been insistent that they do not want Mr. Macron’s image associated with their campaigns.

In many regards, the way Mr. Macron decided to dissolve the National Assembly and call elections appears as Exhibit A in his highly centralized style of governing. Even by the standards of the Fifth Republic, conceived in 1958 to give the presidency enormous powers, Mr. Macron has governed in his own head and by his own edict.

“He never conceded a little of his power to exercise it collectively,” said Hakim El Karoui, a private consultant who works on the immigration issues that have been at the core of the rise of the National Rally.

Even Mr. Macron’s own government has frayed. A group of just four people, among them a former journalist, Bruno Roger-Petit, who advises Mr. Macron on French national memory, dreamed up the idea of a dissolution the night of the European Parliament election, according to an account in Le Monde that has since been widely confirmed.

This led Bruno Le Maire, the economy minister, to describe Mr. Macron’s advisers as “lice,” in a TV interview last week. Mr. Le Maire has had to battle hard to stabilize the French economy since the snap election was called. Unpredictability is not what investors like, and France’s debt had already soared from support for workers and businesses during Covid lockdowns.

Mr. Macron’s former prime minister, Édouard Philippe, widely seen as a likely presidential candidate in 2027, declared this month that “It was the president who killed the presidential majority.” He added, “We’re moving on to something else, and something else can’t be the same as before.”

That much seems near certain. It is likely that the National Rally will be the largest party in the new National Assembly, even if it may well fall short of an absolute majority. It is also likely that Mr. Macron’s party will come in third, behind Ms. Le Pen’s and the New Popular Front representing the left.

This, then, would be the “clarification,” but one that involves redoubled murkiness.

If the National Rally does secure an absolute majority, Mr. Macron may have to name Jordan Bardella, 28, Ms. Le Pen’s popular protégé, as prime minister. Mr. Bardella could then choose his cabinet. France has known “cohabitations” before but never between two men of such diametrically opposed convictions.

Even if the National Rally does not win a majority, Mr. Macron will face a sharply divided Parliament, more ungovernable and less favorable to him than the one he chose to dissolve, with the possibility of political chaos over several months. He has denied he will resign in such circumstances.

Mr. Macron remains immovable in his conviction that he will be vindicated. “I don’t have a defeatist spirit,” he declared recently.

Anne Hidalgo, the Socialist mayor of Paris, was not persuaded. She accused Mr. Macron of spoiling the Olympics. “Why ruin this beautiful moment with an election called at the drop of a hat without consulting anyone?” she asked.

On June 18, Mr. Macron attended a gathering to commemorate Charles de Gaulle’s famous broadcast from London on that day in 1940, calling for resistance to the Nazi occupation of France. The occupation would soon birth the collaborationist French Vichy government, a troubling memory at this moment for the many who fear the far right.

When asked about Mr. Attal by a boy in the crowd, Mr. Macron said, “He could be my little brother.” Soon after, Mr. Attal, 35, who has agreed to lead the centrist campaign in the election, appeared in the same spot and was told of the exchange.

Clearly confused, or incredulous, the prime minister responded: “He said what?”

If nothing else, Mr. Macron’s decision on the snap election has dizzied his compatriots: To what end is the most frequently asked question in France today.