The scenes in the French capital were reminiscent of the historic night in 1998 when France won the World Cup for the first time and the Champs-Élysées was flooded by more than a million fans.
Excited supporters chanted "we are in the final" as they danced and waved the country's national flag, the tricolore.
"I bet €200 on France being world champion," French fan Kilian Guillouzo told CNN, as celebratory red, white and blue smoke billowed above the Parisian streets.
His friend, Nora Wisniewski added: "The whole game was quite stressful but I'm happy with the result and my heart is exploding with happiness."
French President Emmanuel Macron, who was at the match tweeted his support to the national team at full time.
"We're in the finals. See you on Sunday to bring it back," he wrote.
More than 20,000 fans gathered at Paris' historic Hotel de Ville to watch the semifinal on a giant screen, the AFP news agency reported.
But viewing space was at a premium and every vantage spot was occupied -- with fans perched on trees, on top of vans, on dustbins and bus shelters.
Mood in Brussels
The atmosphere was, understandably, more downbeat in the Belgian capital, Brussels.
On a damp and drizzly evening, those gathered in the city's fan zones were left to consider what might have been.
This tournament in Russia was likely the final chance for many of the country's 'golden generation' of players to win football's greatest prize.
"(I'm) very sad," Belgium fan Howard Sebastian told CNN. "Belgium dominated the first half.
"France has a really good defense and that made it very hard."
Tshekina Tahibangu, 19, added: "We played so well so we can't be mad at France."
The Belgian Prime Minister was out in the Braine-le-Comte municipality, mingling and posing for photos with fans.
But he was similarly magnanimous in defeat, as well as complimentary to the country's footballers who had taken the Belgium to only its second ever World Cup semifinal.
"This is an especially fantastic achievement thanks to perseverance and courage!" he wrote. "Respect for our (Red) Devils."