The 57-year-old won 51.6% of the vote in the presidential run-off, unseating the incumbent Nicolas Sarkozy after a fractious campaign in which rising unemployment and the sputtering economy were the key battlegrounds.
After hearing the news in his political power base of Tulle, Mr Hollande travelled to Paris to address the enormous celebration in the symbolic heart of revolutionary France.
"In all the capitals... there are people who, thanks to us, are hoping, are looking to us, and want to reject austerity," he shouted, his voice hoarse.
"You are a movement lifting up everywhere in Europe, and perhaps the world."
Certainly the world has taken notice: he received congratulatory telephone calls from Germany's Chancellor Angela Merkel, US President Barack Obama and British Prime Minister David Cameron.
Mr Hollande has already indicated his first official foreign trip will be to Berlin for a meeting with the German chancellor.
Observers agree that his election represents a sea-change in the governance of the eurozone and the management of the single currency crisis.
Under the outgoing presidency, France and Germany led an austerity drive to enforce budget discipline across the 17 single currency nations.
Now Francois Hollande is promising to amend their signature compact - agreed in principle by all EU nations except the UK and the Czech Republic - to include an enhanced commitment to growth.
Tears streamed down the faces of many supporters of Nicolas Sarkozy at the UMP's makeshift headquarters at the Maison de la Mutualite in central Paris, as he conceded defeat.
"I bear responsibility...for the defeat," he said.
"I committed myself totally, fully, but I didn't succeed in convincing a majority of the French. I didn't succeed in making the values we share, win."
He stopped short of retiring from frontline politics but indicated he would not lead his party into this summer's legislative elections, in which parties previously on the political fringes may make gains.
One of those groups is the Front Nationale led by Marine Le Pen, who scored nearly one-fifth of all the votes cast in the first round.
She was withering of both candidates after the result.
"So Hollande has arrived with promises of big projects. Like Nicolas Sarkozy, first he will let down his supoprters and then he will let down the whole of France," she said.
But the Socialists are hoping their success in the race for the Elysee Palace will presage a tighter control over the entire political landscape of France.
The party already runs most municipalities and the Upper House, called the Senate, so a majority in Parliament would constitute a challenge to the centre-right administrations in most of Europe's major industrialised economies.