Emmanuel Macron has formally taken power as France's new president.
Speaking at a ceremony at the Elysee palace, the 39-year-old told an audience of 300 people that he would do everything necessary to fight terrorism and authoritarianism, and to resolve the world's migration crisis.
Tight security was in place across Paris ahead of the ceremony.
After he was formally declared president, 21 cannon shots were fired from across the Seine River at the Invalides monument, where Napoleon is entombed.
Mr Macron takes over from outgoing President François Hollande.
The two met earlier in the president's office earlier to discuss the most sensitive issues facing France.
Following his inauguration, Mr Macron travelled to the Tomb of the Unknown soldier, at the Arc de Triomphe at the top of the Champs-Elysees Avenue, a tradition followed by all heads of states in France's modern history.
He will also meet Paris Mayor Anne Hidalgo.
Mr Macron, beat far-right wing candidate Marine Le Pen in the second round election run-off last week.
A former economy minister, he quit Mr Hollande's Socialist government last year to form his own centerist political movement, making him the first French president who does not represent one of the country's mainstream parties.
Mr Macron is set to name is prime minister on Monday.