Another Toll of the Violent Unrest in France: The Political Center Support for Édouard Philippe, the leading candidate from the centrist bloc, has eroded, while his far-right and far-left rivals benefit.

Soon after President Emmanuel Macron of France spoke to a traumatized country, in the aftermath of riots that set cities aflame on Oct. 17, Mr. Macron’s former prime minister and aspiring successor, Édouard Philippe, responded to his old boss.

“Our country needs to be commanded,” Mr. Philippe wrote, scolding Mr. Macron for what he called a failure to restore order, protect shopkeepers from looters and engage protesting high-school students in dialogue.

For Mr. Philippe, the leading presidential candidate from France’s shrinking political center, it was not the first break with Mr. Macron. But his tempered tone suggested he was speaking more in sorrow than in anger. It was all but lost in an angry cacophony, underscoring how the upheaval is reshaping France’s politics: More extreme figures are sidelining centrists.

No major candidate has lost more support in the polls than Mr. Philippe since the protests erupted last month: roughly two percentage points, leaving him between 13 percent and 15 percent. He now trails the far-left candidate, Jean-Luc Mélenchon, and remains well behind the far-right leader, Marine Le Pen, who claims the backing of about a third of those surveyed in most polls.

As things stand, Mr. Philippe, 55, would not make it into the second round of France’s two-round election system that starts in April. That would leave voters choosing between Ms. Le Pen and Mr. Mélenchon — a race she would likely win.

“Politics are getting more polarized, with the student movement and allegations of police brutality,” said Philippe Marlière, an expert on French politics at University College London. “The two extremes have their own repertoire for that. The moderate right is being squeezed between these two forces,” he continued. “They are being suffocated. There is no space for them to be heard.”Mr. Philippe joins a beleaguered band of centrist politicians across Europe. Anger over rising prices, stagnant economies and declining prospects for young people has propelled populist parties on the far left and far left. That has flummoxed centrists like Chancellor Friedrich Merz of Germany; Keir Starmer, the ousted prime minister of Britain; and Mr. Macron himself.

A day after the riots, Ms. Le Pen warned about a “profound crisis of confidence and authority.”She spoke at a desk in front of a French flag, in a video that seemed designed to present her as a president in waiting. Mr. Mélenchon lashed out at the government for its handling of the protests, accusing it of “blind violence.”Mr. Philippe, the mayor of the port city of Le Havre, sought to strike a law-and-order message, but less stridently. He met with shopkeepers in Paris whose properties were looted and vandalized. He patrolled with the police in the eastern French city of Charleville-Mézières.

Speaking to Le Point, a conservative French magazine, this week, Mr. Philippe also tried to highlight his right-wing credentials. Young people from immigrant backgrounds were overrepresented among those who rioted, he said, a claim the government has not backed up.

He called it a “failure of integration in our country” and promised to cut in half the number of immigrants to France over the next five years. Mr. Philippe’s representatives acknowledge that France’s fraught mood does not favor a sensible, center-right politician, one best known for serving Mr. Macron during the first three years of his presidency, most visibly during the Covid pandemic. “There is a before and after Oct. 17,” said Arnaud Péricard, a spokesman for Mr. Philippe’s party, Horizons. “It’s a very complicated moment, where a lot of electors are losing their boundaries.”Mr. Philippe had also come under scrutiny in an investigation of embezzlement of public funds involving the city hall in Le Havre. On Thursday, his lawyer confirmed a report in Agence France-Presse that Mr. Philippe had been designated as an “assisted witness” in the case.

That legal status does not clear him but indicates that, for now, there is not enough evidence to charge him. Mr. Péricard said Mr. Philippe’s campaign viewed the development as “very positive,” adding, “This matter is now behind him.”Mr. Philippe’s strategy, he said, was to increase his public visibility in the coming days, but otherwise to ride out the current upheaval without losing his status as the leading centrist candidate. Front-runners in French presidential elections often stumble, Mr. Péricard noted, referring to Ms. Le Pen, and the campaign won’t shift into high gear until January.

“Édouard always describes himself as a diesel,” he said. “He’s slow to accelerate, but once he gets up to pace, he keeps it.”For the moment, Mr. Philippe’s position seems secure, if only because the center is so fractured. His most direct rival on the center right, Gabriel Attal, another former prime minister, has also seen his poll numbers sag since the unrest broke out. Bruno Retailleau, a more hard-line figure, has faced competition from the mayor of Cannes, David Lisnard, an upstart hard-liner with a savvy social-media profile.

On Wednesday, Mr. Attal called for a primary vote to determine which centrist candidate should go on to face the far right and far left.

On the center left, Raphaël Glucksmann, a member of the European Parliament, has also recently enjoyed a modest bounce in polls, though analysts question his staying power. They are waiting to see if François Hollande, the former Socialist president, will enter the race early next year.

Some in France yearn for a fresh face to shake up the race, much as Mr. Macron did in 2017, when he ran as a 39-year-old agent of reform. France’s economics minister, Roland Lescure, said this week that he believed a majority of people would vote for a moderate candidate if the right one emerged.

“We’ll see by the time January or February comes if someone can emerge or maybe some two can emerge” as a unifying figure, Mr. Lescure said to reporters. “There’s a bit of a silent majority that is still out there, that I think requires or demands an incarnation, which we haven’t been able to provide yet.”Political analysts, however, said they were skeptical that any “white knight” would emerge, in part because of the challenges of building a viable campaign on short notice. Even before the recent unrest, the polarization of French politics would make a centrist coalition of the kind Mr. Macron assembled far-fetched today.

“His strength lies in having succeeded in consolidating an electoral base and in having created an electoral base that didn’t exist before him,” said Raphaël LLorca, an analyst at the Jean-Jaurès Foundation, a left-leaning research group in Paris. “Isn’t this, deep down, the end of Macronism, in the sense that each of his voters is returning to their own homes?”Mr. Macron has never been more unpopular than he is now, which poses another hurdle for Mr. Philippe. Although he left the government in 2020, and even called on Mr. Macron to resign last October amid chaos over passing a budget, Mr. Philippe is identified as a veteran of his movement.

“Whatever credibility the government had evaporated on Oct. 17,” said Mujtaba Rahman, an expert on France at the Eurasia Group, a political risk consultancy. “That context is damaging to Philippe by association.”Ségolène Le Stradic and Giulia Imbert contributed reporting.

Mark Landler is the Paris bureau chief of The Times, covering France, as well as American foreign policy in Europe and the Middle East. He has been a journalist for more than three decades.