"With nearly 11 million votes, the far right reaches a sad record in our country tonight", a leading politician of the Socialist Party, Jean-Christophe Cambadélis, said, branding the votes received by Le Pen "confusing and alarming".
Macron reached out to Le Pen's supporters in a plea for unity after a vicious election campaign that exposed deep economic and social divisions, as well as tensions provoked by identity and immigration.
The euro retreated on Monday from highs hit on centrist Emmanuel Macron's victory in France's presidential election, with investors taking profit on a roughly 3 percent gain for the currency since he won the first round two weeks ago.
Macron's victory has eased market concerns over France's leaving the EU and the collapse of the EU, pushing Euro and Europeans stocks further up.
"I know the country is divided and this has led to people voting for extremes", Macron said in a speech at his team's headquarters. "I look very much forward to working with him".
"I understand the anger, the anxiety, the doubt which many of you have expressed and it is my responsibility to hear that".
The philosophy and literature lover is inexperienced, has no political party and must fashion a working parliamentary majority after legislative elections next month.
"Macron's election offers stability to Europe's single market, and strengthens the EU's position in the upcoming Brexit negotiations", Margaret Yang of CMC Markets said in a commentary.
Mr Macron, who hopes to revitalise the Franco-German axis at the heart of the European Union, plans to visit Berlin shortly.
"Congratulations to Emmanuel Macron", the Republican House Speaker Paul Ryan tweeted.
"France has won!" he said. Britain had voted to leave the European Union six months before and the United States had just elected a president who was hostile to their grand project and the values it stood for. Le Pen's proposals included holding a referendum on European Union and euro membership - and experts agree the euro wouldn't have survived the departure of its founding member and second-biggest economy.
Le Pen credited herself with upsetting the French political landscape, creating a divide "between patriots and globalists".
If confirmed, that would be double the score of her father, National Front co-founder Jean-Marie Le Pen, at the same stage in the 2002 presidential election.
Mr Trump had praised Ms Le Pen, although he stopped short of explicitly endorsing her.
On the left, the Socialist Party imploded, its candidate abandoned by voters who wanted to punish Hollande, France's most unpopular president since World War II.
Austria may be the far-right's best hope for a victory, where opinion polls suggest that the anti-immigrant Freedom Party may be able to lead a coalition after elections that must be held by next year at the latest. "I've voted for the left in the past and been disappointed".
The president-elect makes a first official appearance alongside Mr Hollande at Paris' Arc de Triomphe for the annual ceremony at the Tomb of the Unknown Soldier to commemorate Victory in Europe Day and the surrender of Nazi forces on May 8, 1945.
The result is remarkable considering Macron, a centrist independent, campaigned without a traditional party and with no experience of governing.
Le Pen, 48, has brought her far-right National Front party, once a pariah for its racism and anti-Semitism, closer than ever to the French presidency, seizing on working-class voters' growing frustration with globalization and immigration.
Macron will become the eighth - and youngest - president of France's Fifth Republic when he moves into the Elysee Palace after his inauguration next weekend.
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