Emmanuel Macron became the youngest president in French history on Sunday in an inauguration ceremony organized amid high security prompted by the country's persistent terrorist threat.
A week after his victory, Macron, 39, officially took over from the outgoing Socialist president François Hollande, the political mentor who gave him his first high-profile government job.
The red carpet was rolled out and the gravel courtyard at the Elysée Palace raked smooth for Macron's arrival for the ceremonial handover.
A smiling Hollande gave his protegé a warm welcome before the two men disappeared behind the closed doors of the first-floor presidential office for an exchange of nuclear codes and a private handover chat that lasted more than an hour showing the depth of affection between the two men.
Hollande then left the Elysée, accompanied by the Republican Guard in full ceremonial dress, to applause from palace staff.
Brigitte Macron, the new president's wife, arrived separately, followed by around 50 family members.
In his first speech as president, Macron said he understood the "seriousness of the honor" French voters had given him.
"Europe and the world need a strong France that is sure of its destiny. They need a France that shouts in defense of freedom and solidarity," he told diginitaries, officials, politicians and press gathered in the 18th century palace's ornate Salle des Fêtes. The room, opened in 1889 for the Universal Exhibition, drips with gilt cornicing and decoration and crystal chandeliers. Its ceiling is painted with panels representing "The Republic, keeper of the peace" and allegories representing art and science.
"It falls to me to ensure that our country carries in its heart all the materials necessary for being one of the world's most important nations …. I will not back down on promises made," he said.
"I will ensure that our country regains its democratic energy … the people will be listened to."
Afterward's the Elysée's orchestra broke into a rendition of composer Jacques Offenbach's Orpheus in the Underworld, better known as the French Can-Can, and the equally joyful Hungarian Dance No. 5 composed by Brahms. Macron was said to have chosen the music personally.
The president's media team kept the press, many of them invited by personal telephone call the previous evening, updated with helpful information, such as that Macron wore a dark blue, French-made suit and his wife a lavender blue dress with military-style double-breasted jacket while carrying a handbag "borrowed" from luxury fashion house Louis Vuitton. And that the presidential couple would be leaving their home in the French capital's chic 7th arrondissement and moving into the Elysée Palace straight away for security reasons but also so as not to upset their neighbors.
After the formal ceremony, Macron paid tribute to France's war dead at the Tomb of the Unknown Soldier at the Arc de Triomphe, where he met military veterans.
The center of Paris was sealed off as 1,500 police officers deployed around the presidential palace and the Champs Elysées. France has been under a state of emergency since the November 2015 series of bombings and shootings across the city. Ignoring the threat, Macron broke away from his motorcade to shake hands with supporters who lined the world-famous avenue. He then stopped his official car at the spot where police officer Xavier Jugele was shot dead in a terrorist attack last month.
Macron is the first French president to take office in his 30s. The youngest head of state before him was Charles-Louis-Napoleon Bonaparte, known as Louis-Napoleon Bonaparte, who was the nephew and heir of the famous military and political leader Napoleon Bonaparte. He took office in 1848 at the age of 40.
Macron's first challenge is to persuade French voters to give him a parliamentary majority in the National Assembly in legislative elections to take place on June 11 and 18, without which his hands will be tied.
On Monday, he will name his prime minister, who will be asked to form a "transpartisan" government, with representatives across France's political spectrum, as well as business leaders; half the new ministers are expected to be women.
Macron, who was Hollande's economy minister between 2014 and 2016, will then fly to Berlin for his first foreign meeting as president with German Chancellor Angela Merkel. Macron campaigned on closer ties with Germany and Europe, as opposed to his defeated rival, the far-right's Marine Le Pen, who wanted a Brexit-style referendum on leaving the European Union and on dumping the euro.
The new president's political movement, En Marche! (On the Move!), launched only 13 months ago, was transformed into a party after Sunday's victory. Now called La Republique En Marche (La REM), it has already named 428 candidates, just over half of whom have no political experience, and half who are women. The list includes former bullfighter Marie Sara, French air force "top gun" fighter pilot Marion Buchet, and math genius Cedric Villani, who won the 2010 Fields medal, considered the equivalent of the Nobel Prize in mathematics. La REM has to find another 148 candidates to fill slots before the registration deadline Friday.
Willsher is a special correspondent.
10:10 a.m.: This article was updated throughout with staff reporting, additional details and background.
6:05 a.m.: This article was updated with additional details about Macron's inauguration, as well as background on the French political climate.