Laurens gave trainer Karl Burke and jockey PJ McDonald their first taste Classic success with victory in the Prix de Diane – France’s equivalent of the Oaks – at Chantilly.
The 7-1 shot, runner-up in the 1,000 Guineas at Newmarket, won her third prize at flat racing’s Group One level.
Musis Amica finished strongly to grab the runner-up spot ahead of Homerique, Aidan O’Brien’s Happily and With You.
“She’s a superstar,” said owner John Dance. “She’s proved she’s top-class.”
Laurens rounded off her juvenile campaign with a Group One triumph in the Fillies’ Mile at Newmarket last October and also won the Prix Saint-Alary at Longchamp three weeks ago.
Dance told The Racing Post: “When we bought the filly this was the race we talked about, literally the day we bought her, so to actually come here and win it, it’s incredible.
“She’s French-bred and she obviously loves France and coming back home.
“She’s achieved so much already, it seemed a bit greedy to think she could win again today.”
BBC horse racing correspondent Cornelius Lysaght
What a magnificent performance by Laurens, who took over the lead from her position on the outside of the runners with still more than 400 metres of the 2,100m to go.
Her rivals lined up to take her on, but the filly, again beautifully handled by jockey PJ McDonald, was having none of it and saw them all off in style.
In the process, Laurens gave herself, McDonald, Karl Burke and everyone else involved their biggest wins, and she’ll likely be a significant player in some major prizes in the near future.
With that gritty attitude, she could give both male and older rivals plenty to think about.