In his inaugural speech to some 400 guests, Hollande said he was aware of the challenges ahead, including the debt crisis, and vowed to “open a new path in Europe”.
Marking his differences with outgoing President Nicolas Sarkozy, who some faulted for being all-controlling and too impulsive, Hollande said he would run a “dignified” and “sober” presidency and ensure parliament plays its full role.
“I will set the priorities but I will not, decide for everyone, on everything and be everywhere,” Mr. Hollande said.
Hollande, whose election comes as the euro zone is teetering back into crisis over fears about Greece’s future in the single currency, will give his first presidential news conference in Berlin in the evening, flanked by the centre-right Merkel.
His comments will be keenly watched by financial markets eager for re-assurance that his push to tack pro-growth instruments onto Europe’s budget discipline treaty will not sour the start of his relationship with Merkel.
Jean-Pierre Jouyet, a friend of three decades and a seasoned European affairs specialist, said the Berlin meeting was sure to go well but that this did not mean Hollande would be unable to press his case with Merkel for a more pro-growth strategy.
“It will go well in terms of form because Francois Hollande is courteous and so is Angela Merkel,” Jouyet, head of France’s financial markets regulator, told RTL radio.
“In terms of substance, neither has lessons to give the other.”
Any indications on initial economic policy will be scrutinised both outside France and inside, where frustration over rampant unemployment and a sickly economy were key factors behind conservative Nicolas Sarkozy’s defeat.
Hollande, who said on the night of his election that the weight of events in Europe forced him to keep his celebrations short, said on Monday he knew he would be judged on how he starts his presidency.
Hollande was officially sworn in a president just before 11 a.m. (0900 GMT) in a ceremony after Sarkozy greeted him on the steps of the Elysee presidential palace and took him inside to hand over the country’s nuclear codes and other secret dossiers.
Anxious not to lose the “Mr Normal” image that appealed to voters tired of his showman predecessor, Hollande had asked for the inauguration ceremony to be kept as low-key as possible.
He invited 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 attended his swearing-in.
Still, the man who until recently went to work on a scooter was presented with the official chain of office, a gold collar weighing nearly a kg engraved with his name and the six previous presidents of the Fifth Republic.
He also had a Legion of Honour medal pinned on his lapel.
He was later be taken on a traditional victory drive down the Champs Elysees avenue in an open-topped car.
Hollande is set to name civil servant Pierre-Rene Lemas as his chief of staff later in the day, while Germanophile Jean-Marc Ayrault, who has strong contacts in Berlin, could be named prime minister sometime after that.
Before that, Hollande will eat his first lunch as president with Socialist former prime ministers Pierre Mauroy, Laurent Fabius, Michel Rocard, Edith Cresson and Lionel Jospin.
Mr. Hollande will travel to the U.S. on Thursday for G8 and NATO summits after holding his first cabinet meeting.