PARIS — Not since World War II has the anti-immigrant far right been closer to gaining power in France. With her second-place finish on Sunday in the first round of the presidential election, Marine Le Pen has dragged her National Front party from the dark fringes of its first 40 years.
But that remarkable accomplishment is so alarming to so many in France that as soon as the preliminary results were announced at 8:01 p.m., virtually all of her major opponents in the 11-person race called for her defeat in the second-round runoff on May 7. They implored their supporters to vote for the candidate projected to come out on top on Sunday, the centrist, pro-European Union former economy minister Emmanuel Macron, a political novice and outsider.
The first-round showing by Mr. Macron and Ms. Le Pen represented an earthquake, as they effectively broke the French political establishment. On the right and the left, the two parties that have governed France for more than 50 years suffered a severe defeat. They have been pushed aside in a wave of popular anger over the country’s stagnant economy and shaky security.
Ms. Le Pen has oriented her appeal around what analysts and politicians call the “un-demonization” of her party — the shedding of its racist, anti-Semitic, Nazi-nostalgic roots. That strategy has scored big results. Until the last week of the campaign, when she turned even more sharply anti-immigrant, her speeches were shaped around what she depicted as regaining France’s “sovereignty,” breaking with the European Union and “restoring” France’s frontiers.
But an undercurrent of prejudice still undergirds the National Front’s fervent rallies. Anti-Muslim code still permeates her speeches. And a majority of French people, in polls, still say the party represents a threat to the country’s democracy.
That sentiment was widely evident on Sunday in declarations from the political class, and from voters themselves. True, polls and prognosticators failed to predict Britain’s vote to leave the European Union, or the American presidential victory of Donald J. Trump. It is because of these unexpected shocks to the political status quo that many analysts are wary of prematurely writing off Ms. Le Pen. But early polling for the second round in France shows that Mr. Macron’s margin over her is as high as 25 percent.
One after another on Sunday night, and in quick succession, the grandees of the established parties urgently called for an anti-Le Pen vote, as if the real stakes of this year’s election had suddenly been revealed.
“Extremism can only bring unhappiness and division,” said the defeated candidate of the center-right Républicains party, François Fillon, who was the consensus favorite four months ago but was brought down by a corruption scandal. “There is no choice but to vote against the far right,” said Mr. Fillon, who was set to finish in third place.
The candidate of the governing Socialist Party, Benoît Hamon, whose fifth-place finish symbolized voter rejection of the establishment, was equally unequivocal. He had run a campaign of unrelenting hostility toward Mr. Macron. That vanished Sunday. “There’s a clear distinction to be made between a political adversary and an enemy of the republic,” Mr. Hamon said, calling on Socialists to vote for Mr. Macron. “This is deadly serious now.”
Only the likely fourth-place finisher, the far-left candidate Jean-Luc Mélenchon, was holding back on Sunday night, hoping for an as-yet uncounted big-city vote that might push him past Ms. Le Pen. But his supporters were already acknowledging what appeared to be inevitable and calling for a Macron vote in the second round.
Fifteen years ago, when Ms. Le Pen’s father, Jean-Marie Le Pen, shocked his compatriots by breaking through to the second round and again knocking out the Socialist Party, some Socialist voters went to the polls with clothespins on their noses, as they voted for the scandal-plagued candidate of the center-right, Jacques Chirac. Mr. Le Pen was dealt a crushing defeat.
Eighteen months ago, in widely watched regional elections, Ms. Le Pen’s party seemed all but certain to gain control of the two regions in France where it is strongest, the north and the southeast. Most analysts predicted it. In the end, she gained neither: In the second round of those contests, the “Republican Front” united against her, the right and the left, and the National Front failed to gain a single region.
This time, even though she has pushed her party into a second round of voting, her prospects based on the first round do not necessarily look bright, either. She underperformed, gaining 21 percent of votes to Mr. Macron’s nearly 24 percent. Analysts said the result could be seen as a disappointment for the Front, based on polls before the vote.
“She’s clearly done better than in 2012,” said Joël Gombin, a Front expert at the University of Picardy Jules Verne, calling it a half-victory. “But at the same time, the result is below what the Front was hoping for, and what the polls were saying.”
Mr. Gombin said the results suggested the Front could also fare poorly in crucial legislative elections in June. In order to prevail against Mr. Macron, Ms. Le Pen must gain the votes of over half the Fillon supporters, Mr. Gombin has said. But no poll shows her as achieving that result within a Fillon electorate that is conservative but hardly radical.
“The Front was unable to get voters on the right,” Mr. Gombin said. “And it does seem as though the dynamic of the Republican Front will prevail,” he added. “For the moment, I can’t say there will be any cracks in it.”
Mr. Gombin predicted a rejection inside the Front of the centrist-oriented turn pushed by technocrats like Ms. Le Pen’s closest adviser, Florian Philippot, and a return to its hard-right roots.
Mr. Philippot was in television studios on Sunday night, ostensibly relishing the sharp ideological battle to come with Mr. Macron, who rejects Ms. Le Pen’s economic protectionism and is strongly in favor of France’s European partnerships.
“We’ve been able to impose this idea of patriotism at all levels,” Mr. Philippot said. “It’s really going to be about private interests” — the Front regularly derides Mr. Macron as the candidate of the “banks,” as he is a former investment banker — “against the interests of the nation.”
But at polling places on Sunday in Paris, voter after voter expressed fear of a Le Pen victory, even if there was no great enthusiasm for the youthful, untested Mr. Macron. Many said they had difficulty even stomaching the prospect of the National Front making it to the second round.
“That Marine Le Pen is not in the second round — that’s what I want,” Fabienne Zellner, who runs a youth-aid agency, said outside a polling station in Paris’s heavily immigrant 18th Arrondissement. “That’s what I want.”
Myriam Bellehigue, a university professor in the more bourgeois Ninth Arrondissement, voted for Mr. Macron “without much” enthusiasm. “But, and I’ve been saying it for weeks,” she said, “the extremes are just not possible.”