Olympic bronze medallist Sally Conway beat world champion Chizuru Arai to win -70kg gold at the Paris Grand Slam and become the first British champion at the event since 2003.
The 31-year-old held down Japanese judoka Arai for ippon with 20 seconds left on the clock.
It is the first time she has beaten the 24-year-old world number one.
Conway was the first British finalist in Paris since 2004, and only the sixth Briton to win a title.
"I don't think it's even really sunk in yet," said Conway, who won bronze in Paris in 2016. "Listening to the national anthem in this amazing Bercy Stadium was just the best feeling ever."
The world number 26 started her day with a solid victory over Melissa Heleine, throwing the Frenchwoman for ippon.
She then defeated Swedish world number six Anna Bernholm with a late waza-ari.
Golden score was required against world silver medallist Maria Perez of Peru, with Conway securing her place in the semi-finals with a juji before she overcame French world number three Marie Eve Gahie to progress to the final.
Craig Fallon was the last Briton to win in Paris in 2003, two years before he won -60kg gold at the World Championships in Cairo.
Conway's gold was Great Britain's third medal at the 2018 Paris Grand Slam, with Nekoda Smythe-Davis and Ashley McKenzie both winning bronze on Saturday.
Wales' Natalie Powell finished seventh in the -78kg on Sunday after defeats by Japan's Shori Hamada, and Karen Stevenson of the Netherlands.