Socialist leader Francois Hollande has been sworn in as the 24th president of France after his predecessor Nicolas Sarkozy handed power in a ceremony at Elysee Palace in Paris.
Hollande, who becomes the country's first left-wing head of state in 17 years , was later due to fly to Berlin to meet German Chancellor Angela Merkel for urgent talks on the future of the eurozone.
Hollande, whose election comes as the bloc is teetering back into crisis with fears about Greece's future in the single currency, will give his first presidential news conference in Berlin in the evening with Merkel.
He was also set to make the much-anticipated announcement of who will lead his government as prime minister, with Jean-Marc Ayrault, the head of the Socialists' parliamentary bloc, tipped as frontrunner.
Other contenders include Martine Aubry, the Socialist Party leader and former labour minister, Manuel Valls, Hollande's communications director during the campaign, and Pierre Moscovici, his campaign and transition chief.
Nine days after he defeated right-winger Nicolas Sarkozy in a fierce campaign, the Socialist's first words as president will be keenly watched by financial markets eager for reassurance that his push for more economic growth against austerity measures will not sour the start of his relationship with Merkel.
Before that, Sarkozy will go through the ritual of entrusting his successor with nuclear codes and other secret dossiers, and Hollande will eat his first lunch as president joined by several former Socialist prime ministers.
-French presidential swearing-in ceremony
At 14:00 GMT, Hollande will fly to Berlin, where he faces an uncertain reception from Merkel, a Sarkozy ally and the main backer of the European Union's fiscal austerity drive. Hollande has vowed to refocus European economic policy on growth by re-opening talks on a fiscal pact agreed in March that aims to control European debt by enshrining greater budget discipline.
Merkel has repeatedly insisted since Hollande's election that the pact, signed by 25 of the 27 EU countries and already ratified in some, is not open to renegotiation.
But observers say there could be room for manoeuvre, with Hollande likely to agree to additional stimulus measures without a complete rewrite of the agreement. The possible appointment as prime minister of Ayrault, a German speaker with strong contacts in Berlin, could also point to rapprochement between the leaders of Europe's two largest economies.
And with political paralysis in Greece raising the spectre of the country being forced from the eurozone, both Merkel and Hollande will be keen to reassure worried markets they can work together.
Hollande takes over at a time when French debt has swelled to 90 per cent of GDP, the trade deficit is at a record $90bn and nearly one in four young French workers is unemployed. The public sector accounts for 56 per cent of annual output, higher than in any other European country.
Hollande, who said on the night of his election that the weight of events in Europe had forced him to keep his celebrations short, said on Monday he knew he would be judged on how he started his presidency.
Anxious not to lose the down-to-earth image that appealed to voters tired of his predecessor Nicolas Sarkozy, Hollande has asked for his inauguration ceremony to be kept as low-key as possible.
In a break with tradition, he will invite just three dozen or so personal guests to join some 350 officials at the event and neither his nor his partner Valerie Trierweiler's children will attend.
He will be presented with the official chain of office, a gold collar engraved with the names of all Fifth Republic presidents before being taken on a traditional procession down the Champs Elysees avenue in an open-topped car.
Hollande is expected to name civil servant Pierre-Rene Lemas as his chief of staff shortly after his swearing-in.