The International Olympic Committee (IOC) revealed Paris will host the 2024 event while Los Angeles gets the 2028 slot.
It comes after a year of bargaining by IOC president Thomas Bach, who had only the two bidders left for the original prize, 2024, and reportedly could not bear to see either lose.
The move marks the first time two cities have been granted host status for the summer event simultaneously.
Paris 2024 will mark the 100th anniversary of the French capital's last Olympics, while LA's success will halt a dry spell of 32 years for the US.
It will be the third time hosting for both cities.
All the dramatic flair of the usual unveiling of successful bids was done away with this year, with Mr Bach simply asking for a show of hands.
But there were still emotional celebrations in France and the US.
Paris bid organiser Tony Estaguent choked up during the presentation before the vote.
"You can't imagine what this means to us. To all of us. It's so strong," he said.
Later, Paris mayor Anne Hidalgo stood by Mr Bach's side and dabbed away tears as the vote was announced.
Announcements on the city's metro system rang out in French and English bearing the news, and dazzling Olympic rings were unveiled opposite the Eiffel Tower.
President Emmanuel Macron said the news was a recognition of France's "image and values" and of French "willingness to spread these values in today's world".