The 39-year-old has become the youngest president in the country's history after beating his far-right contended Marine Le Pen earlier this month.
He is the first French president who does not originate from the country's two mainstream parties.
After Macron was formally declared president at the Elysee Palace in Paris, 21 cannon shots were fired from across the Seine River at the Invalides monument, where Napoleon is entombed.
Before the ceremony, Macron met for an hour with his predecessor, Francois Hollande.
In a visibly moving moment for both, Macron accompanied Hollande to his car, shaking hands and applauding him along with the employees of the French presidency who had gathered in the palace's courtyard.
The two men had known each other well. Macron was Hollande's former adviser, then his economy minister from 2014 to 2016, when Macron quit the Socialist government to launch his own independent presidential bid.
In his inauguration speech Sunday, Macron said he will do everything necessary to fight terrorism and authoritarianism and to resolve the world's migration crisis. He also listed "the excesses of capitalism in the world" and climate change among his future challenges.
"We will take all our responsibilities to provide, every time it's needed, a relevant response to big contemporary crises," he said, the Associated Press reports.
Macron announced his determination to push ahead with reforms to free up France's economy and pledged to press for a "more efficient, more democratic" EU. France is a founding member of the 28-nation bloc and its third-largest economy after Germany and Britain.
Macron will take his first trip abroad as president on Monday to Germany to visit Chancellor Angela Merkel in Berlin.
Macron will also have to name his prime minister and form a government in the next few days.