Centrist candidate Emmanuel Macron and far-right populist Marine Le Pen have advanced to the French presidential run-off vote, overhauling the country's political system and setting up a showdown over its participation in the European Union.
French politicians on the left and right immediately urged voters to block Ms Le Pen's path to power in the May 7 vote, saying her virulently nationalist anti-EU and anti-immigration politics would spell disaster for France.
The selection of Ms Le Pen and Mr Macron presents voters with the starkest possible choice between two diametrically opposed visions of the EU's future and France's place in it.
It sets up a battle between Mr Macron's optimistic vision of a tolerant France with open borders against Ms Le Pen's darker, inward-looking platform calling for closed borders, tougher security, less immigration and dropping the shared euro currency to return to the franc.
With Ms Le Pen wanting France to leave the EU, and Mr Macron proposing even closer co-operation between the bloc's 28 nations, the outcome of the first round of voting on Sunday after a wildly unpredictable and tense campaign means the run-off will have undertones of a referendum on France's EU membership.
The absence in the final vote of candidates from either the mainstream left Socialists or the right-wing Republicans party - the two main groups that have governed post-war France - also marks a seismic shift in the nation's political landscape.
With 34% of the vote counted, the Interior Ministry said Ms Le Pen was leading on 24.6% followed by Mr Macron on 21.9%.
The early vote count includes primarily rural constituencies that lean to the right, while urban areas that lean left are counted later.
Mr Macron, a 39-year-old investment banker, made the run-off on the back of a grassroots start-up campaign without the backing of a major political party.
Defeated conservative candidate Francois Fillon said he would vote for Mr Macron on May 7 because Ms Le Pen's programme "would bankrupt France" and throw the EU into chaos.
He also cited the history of "violence and intolerance" of Ms Le Pen's far-right National Front party.
In a brief televised message less than 30 minutes after the last polling stations closed, Socialist Prime Minister Bernard Cazeneuve also urged voters to back Mr Macron "to beat the National Front and block its funereal project of regression for France and of division of the French".
Socialist presidential candidate Benoit Hamon, who was far behind in Sunday's results, quickly conceded defeat. Declaring "the left is not dead," he urged supporters to back Mr Macron.
Macron supporters at his election day headquarters in Paris went wild as news that he would advance to the final round emerged, cheering, singing La Marseillaise anthem, waving French tricolour and European flags and shouting "Macron, president!".
Mathilde Jullien, 23, said she is convinced Mr Macron will be able to win over Ms Le Pen and become France's next president.
"He represents France's future, a future within Europe," she said. "He will win because he is able to unite people from the right and the left against the threat of the National Front and he proposes real solutions for France's economy."
But Le Pen supporters were equally enthusiastic.
With a broad smile, Ms Le Pen stood before an adoring crowd and said her National Front party will represent "the great alternative" to the French people and pledged to open a "much-needed" debate on globalisation.
"We will win!" Le Pen supporters chanted in her election day headquarters in the northern French town of Henin-Beaumont. They burst into a rendition of the French national anthem, and waved French flags and blue flags with "Marine President" inscribed on them.
Sunday's vote took place amid heightened security in the first election under France's state of emergency, which has been in place since the gun and bomb attacks in Paris in 2015.
In Paris, protesters angry that Ms Le Pen has advanced into the final vote scuffled with police.
Crowds of young people, some from anarchist and "anti-fascist" groups, gathered on the Place de la Bastille in eastern Paris as results were coming in from the first round vote.
Police fired tear gas to disperse an increasingly rowdy crowd and riot police surrounded the area.
Protesters staged demos at several of Ms Le Pen's campaign events, angry at her anti-immigration policies and her party.