The former investment banker, who had never contested an election before and only formed his centrist political movement a year ago, has vowed to shake up the country's political order and reinvigorate its economy.
A visit to French troops in Mali planned for next Friday was a strong symbol of his commitment to pursue France's military and peacekeeping role in the Middle East and Africa.
"Probably the biggest success of Emmanuel Macron is having motivated so many people who were outside of politics to have committed themselves to try to renew things", his spokesman Benjamin Griveaux said on Friday.
If he fails, he knows he could wind up like his predecessor, the socialist Francois Hollande, who promised to bring change, but ended up being viewed as weak and indecisive, and who leaves office as France's least popular president of modern times.
Brigitte's three children were also present at the ceremony along with VIPs from France's political scene and the young team of close advisers behind Mr Macron's sensational rise.
Macron, once Hollande's economy minister, then accompanied his former mentor down the red carpet to a waiting vehicle.
Mr Macron and Mr Hollande will withdraw for about half an hour to discuss matters of state in private. Still, Macron's vote was equal to 44 percent of registered voters and that's about average for the winners of France's 10 presidential elections.
He tweeted that "we lived through crises but we held together".
He said France's place was in the European Union "which protects us and enables us to project our values in the world" but that the 28-member bloc needed to be "reformed and relaunched".
He then chose to be driven by military jeep rather than civilian limousine to the Arc de Triomphe, where he stood in the rain, without coat or umbrella, to light the flame in tribute to France's war dead at the tomb of the unknown soldier - a powerful reminder of France's role in the North Atlantic Treaty Organisation defense alliance. The warm spring day in Paris was punctuated by showers, prompting one observer to joke on Twitter that it was a "very Macronian" inauguration: "it's raining AND AT THE SAME TIME it's lovely".
Mr Macron also suggested he would press on with his ambitious but controversial agenda to reform France's rigid labour market and modernise the social security system despite the fierce resistance he is likely to meet. He has pledged to push for increased integration of countries that use the euro currency, a step that would mean rich nations like Germany would have to pay more to support poorer ones like Greece. It has announced an initial list of 428 candidates for the 577 seats up for grabs in France's lower house of parliament in the vote on June 11 and 18.
"I am not handing over power to a political opponent, it's far simpler", Hollande said.
On Monday, Macron is expected to reveal the closely-guarded name of his prime minister, before flying to Berlin to meet German Chancellor Angela Merkel. The presidential campaign is done, but Macron's fight is not over. Macron will seek to reassure voters on the left and the right that he is not moving too far away from them - all while emphasizing his newcomer bona fides. They include Marion Buchet, a French air force fighter pilot who served in Syria; and former bullfighter Marie Sara, who will stand in the Gard, in the south of France, against the National Front heavyweight, Gilbert Collard.