Macron is the eighth president of France's Fifth Republic, created in 1958.
After a warm welcome from outgoing President Francois Hollande at the Elysee Palace at around 10:00 a.m. local time (0800 GMT), Macron and Hollande held a closed-door meeting during which Macron was handed the codes to launch France's nuclear arsenal.
Macron won the election with 66% of the votes in the runoff against leader of the far right National Front party Marine Le Pen.
Mr Macron, France's youngest leader since Napolean, takes charge of a nation that, when Britain leaves the European Union in 2019, will become the EU's only member with nuclear weapons and a permanent seat on the UN Security Council.
Macron promised to tackle political, economic and social problems while restoring France's global standing. The two huddled privately for an hour, and then Hollande departed the presidential palace for the last time in a modest Citroen sedan.
Deputy White House Press Secretary Gives Briefing in Wake of Comey Firing
He or she may not succeed at doing that most of the time, especially with the clearly anti-Trump mainstream media. And the big question, one source said, is whether it's temporary or permanent.
Macron, who has shaken up French politics with his meteoric rise to the presidency, said he will do everything that is necessary to fight terrorism and authoritarianism and to resolve the world's migration crisis.
"The world and Europe are more than ever in need of France".
In a visibly moving moment for both, Macron accompanied Hollande to his vehicle, shaking hands and applauding him along with the employees of the French presidency who had gathered in the palace's courtyard.
A 21 gun salute at the Esplanade des Invalides behind the Eiffel Tower after he takes power will mark at least a pause in the anti-globalization trend that brought Donald Trump the USA presidency and led British voters to pick a future outside the European Union.
The new president is also expected to name the country's prime minister in the next few days.
DD v RCB: Kohli falls for 58 | VIVO IPL 2017
Prior to the start of the season, no one could have imagined that RCB would be the first team to be eliminated from the contest. It was surprising that RCB opted for the 20-year-old in only their last game of what has been a forgettable season.
At the end of the formalities, a 21-gun salute is to ring out from the Invalides military hospital on the other side of the River Seine. Mr Macron takes his first presidential trip on Monday to Berlin to meet Germany's Chancellor Angela Merkel.
Macron was later to be driven to the Arc de Triomphe to lay a wreath at the tomb of the unknown soldier.
He wore a dark suit that cost 450 euros ($491), made by his usual Paris tailor, his aides said by text message.
(AP Photo/Thibault Camus). Tiphaine Auziere, daughter of Brigitte Macron, arrives for the inauguration ceremony of incoming French President Emmanuel Macron at Elysee palace in Paris, France, Sunday, May 14, 2017.
Further ahead in June, Macron will need to win a majority in parliamentary elections to enact his ambitious reform agenda.
Senate panel seeks Flynn documents in Russia probe
Under questioning from Sen. "You have someone who you have to wonder whether - why they are telling you something", Spicer added. The White House has officially blamed Comey's handling of the Clinton investigations for his firing.
Hollande's five years in power were plagued by a slow economy and bloody terror attacks that killed more than 230 people. Macron, once an aide to Hollande and who rose to prominence as his economy minister between 2014 and 2016, might therefore struggle to get the country behind him.