Avenir Certain has completed the French 1000 Guineas and Oaks double to join such greats as Zarkava and Divine Proportions in winning both of France's fillies classics.
Given an excellent ride by Gregory Benoist on Sunday, Avenir Certain produced a blistering turn of foot to sweep past the leaders in the straight to give trainer Jean-Claude Rouget his third win in the race.
Favourite Shamkala, bidding to give trainer Alain de Royer Dupre his seventh win in the race and owner the Aga Khan his eighth, finished a disappointing fourth while English 1000 Guineas winner was unplaced.
Rouget, whose training base is in the relatively unfashionable south west of France, was visibly moved by the victory and he said he saw a resemblance between his champion and who won the race in 2008 and went on to win the Prix de l'Arc de Triomphe.
However, despite her earning a quote of 14/1 for the Arc, Rouget is not certain she will run.
"People don't realise how hard it is to get the horse right on the day and to prepare them for these big occasions," Rouget said.
"We thought she was a bit special but it was a high-class field, but Gregory rode her perfectly.
"I had only given him one bit of advice and that was not to panic, and he didn't.
"She made me think a little bit of Zarkava. Avenir Certain won the Poule d'Essai des Pouliches in soft ground and she won this on good ground, so she is quite straightforward. I don't really want to make a decision about her autumn program yet.
"Naturally, every trainer thinks about the Arc but I'm not sure it is the right race for her.
"I think she might stay, but, as I said, we shall see how things go. However, right now she is going to have a well-deserved break."