Always close to the pace-setting Afandy over the intermediate six-and-a-half-furlong trip, the Aga Khan Studs-owned Samangan battled through the final quarter-mile to master Stolen Kiss and just found the post coming in time to foil the William Haggas-trained Division, who flashed home under James Doyle.
The winner had been fourth in the Prix Jean Prat last time out in which True Love was second, but comprehensively reversed form with the Ballydoyle Classic heroine on this occasion.
Nemone Routh, racing manager for the owners in France, told Sky Sports Racing: "He's a lovely horse, he's very genuine. He was always going to follow Afandy and then he was really brave.
"He could (go to Ascot on Champions Day), but I think he's better on good, firm ground, that's another thing we've found this year. I think if it got too soft he wouldn't go there. He's a relaxed horse and he can get seven (furlongs). It all depends on the ground."
Graffard added: "I am very pleased for the stable. He is a colt we have always held in high regard. Things did not go as planned at the beginning of the season, but he also needed to gain experience.
"His previous races have toughened him up and this victory is the result of the experience he has been able to acquire.
"His next target could be the Qatar Prix de la Foret, provided the ground is not too testing for him. He is a Group One winner and exceptionally well bred, so he has earned his place at stud as a stallion. My job is done!"
Distant Storm boosted star three-year-old milers Bow Echo and Gstaad as he made a winning reappearance in the Prix Daphnis.
Third to Bow Echo in the 2000 Guineas at Newmarket before finding only Gstaad too good in the Irish equivalent, Charlie Appleby's colt had been off since that run at the Curragh.
Returning to the track in Group Three company, Billy Loughnane's mount was a little tight for room before getting out to give chase to well-backed Italian raider Grand Son Of Dark.
The Godolphin runner had a fair bit to do but always gave the impression he would get there and he duly did, to set up a return to bigger and better things.
Loughnane said: "I ended up a little further back than ideal, but the pace was even which was ideal and when I popped him out the top of the straight he had a target to run at.
"He's a horse that doesn't do too much when he's there, so having a horse to aim at was good and he won cosily in the end. He's horse that has a nice turn of foot, he takes a bit of time to pick up but when he does he's electric through the line.
"I was pretty confident I had everything covered."
