PARIS — Emmanuel Macron, a youthful former investment banker and political novice, handily won France’s presidential election on Sunday, defeating the staunch nationalist Marine Le Pen after voters firmly rejected her far-right message and backed his call for centrist change, according to projections based on preliminary results.
Mr. Macron, 39, will become the youngest president in the 59-year history of France’s Fifth Republic, after leading an improbable campaign that swept aside France’s establishment political parties.
The election was watched around the world for magnifying many of the broader tensions rippling through other Western democracies, including the United States: populist anger at the political mainstream, economic insecurity among middle-class voters and rising resentment toward immigrants.
Mr. Macron’s victory offered significant relief to the European Union, which Ms. Le Pen threatened to leave. His platform to loosen labor rules, make France more competitive globally and deepen ties with the European Union was also likely to reassure a global financial market jittery at the prospect of a Le Pen victory.
Her loss provided further signs that the populist wave that swept Britain out of the European Union and Donald J. Trump into the White House may have crested in Europe, for now.
“It is a great honor and a great responsibility,” Mr. Macron said, using a video link to address thousands of flag-waving supporters who gathered on the plaza of the Louvre, where he held his victory celebration. “A new page is opening.”
Projections based on early returns gave Mr. Macron 65 to 66 percent of the vote, compared with Ms. Le Pen’s 34 to 35 percent.
The outcome was nonetheless a watershed for Ms. Le Pen’s party, the far-right National Front, giving it new legitimacy even as the results showed that the party remains anathema to much of the French electorate for its history of anti-Semitism, racism and Nazi nostalgia.
The election was groundbreaking for including two political outsiders, as well as for its rancor and an apparent attempt to sway the vote with the large-scale hacking of Macron campaign emails, similar to the attack directed at last year’s election in the United States.
But although Mr. Macron won by a wide margin, the share of votes that went to Ms. Le Pen and the high abstention rate — the worst turnout since 1969 — indicated the challenges he faces in building a base of support for his program.
Ms. Le Pen conceded the election not long after polls closed in France, saying voters had chosen “continuity,” denying Mr. Macron his outsider status and linking him to the departing Socialist government, in which he served as economy minister.
The vote was a record for the National Front and, she said, a mandate for it to become a new “patriotic and Republican alliance” that would be “the primary opposition force against the new president.”
She added that the new political divide would be between “patriots and globalists” and that her party would transform into a new political force reflecting all those who voted for her.
Early returns, according to Ms. Le Pen, showed she would receive 11 million votes, which would be twice the number her father, Jean-Marie Le Pen, received when he ran a losing presidential campaign against Jacques Chirac in 2002.
The estimated 34 to 35 percent of the vote Ms. Le Pen received was the highest share the French have given to her party.
The election was also the first in which the National Front candidate, rather than being a pariah who was shut out of debates and kept off the front pages of major newspapers, as happened in 2002, was treated more like a normal candidate despite the party’s anti-Semitic and racist roots.
Still, Ms. Le Pen clearly failed to convince a decisive portion of voters that her party really had changed. Many of the votes Mr. Macron received on Sunday were no doubt cast not so much in support of him, but in rejection of Ms. Le Pen.
Mr. Macron formed his political movement, En Marche! (Onward!), a little more than a year ago. He was initially given a slim chance of winning in a country that has never elected a president from outside the traditional parties, the Socialists on the left and the Republicans on the right.
Mr. Macron’s campaign benefited from canny timing and no small dose of luck, with the collapse of the governing Socialist Party under President François Hollande, the incumbent, who was so unpopular that he took the extraordinary step of not seeking re-election.
Mr. Macron received another strong boost from an embezzlement scandal that damaged the candidacy of the center-right candidate François Fillon, who at the start of the campaign seemed certain to claim the presidency.
Mr. Macron has already started to try to build support in Parliament, where he has no party to support him.
His message — that his new movement is neither right nor left, but represents a third way, with elements of both — seemed to have appealed to numerous urban voters as well as to many young voters.
As the results appeared on a screen set up at the Louvre, Macron supporters shouted with joy. Some started singing the Marseillaise, the French national anthem.
“This is a historic moment,” said Jacques Pupponi, 60, who came with his children, Noé, 11; Dora, 12; and Eden, 13. “I’ve lived moments like this before, in 1981,” he said, referring to the election of the Socialist president François Mitterrand. “I’m very happy about the score — it’s very, very important,” Mr. Pupponi added, referring to Mr. Macron’s decisive victory.
For Mourad Djebali, 30, a Tunisian engineer who obtained French citizenship a few months ago, the result felt like a personal affirmation. “I’m moved,” Mr. Djebali said. “I recognize the France that has received me.
“It’s a great symbol of France,” he added. “It’s a sign of hope. Everyone doesn’t agree with each other, but that one thing we agree on is that we should not open the door to the extremes.”