The Karl Burke-trained Laurens won the Prix de Diane Longines - the French Oaks - at Chantilly on Sunday.
Ridden by P J McDonald, Laurens (13/2) was never far off the pace set by Frankie Dettori on Luminate and she toughed it out after taking up the running a couple of furlongs from the finish.
Godolphin's Musis Amica came from the clouds to take second, while Homerique was third. Aidan O'Brien's Happily suffered a disrupted passage but flew home at the finish to be fourth, just missing out on the places.
Laurens, who finished second in the 1000 Guineas at Newmarket, was claiming the third Group One win of her career after landing the Fillies' Mile at two and the Prix Saint-Alary at ParisLongchamp on her last start.
She broke smartly from her outside berth in stall 12 and although she was trapped wide throughout, she was still travelling strongly at the top of the home straight.
Former jumps jockey McDonald had to get to work with two furlongs to run, but Laurens answered his every call to see off all comers and claim a popular success.