Full Mast was named the winner of the Prix Jean-Luc Lagardere at Longchamp after first past the post Aidan O’Brien’s Gleneagles was demoted to third by the stewards.
Having wracked up a four-timer with victory in the Vincent O'Brien National Stakes at the Curragh, the O'Brien-trained Gleneagles was a 9-4 shot for his Paris assignment, with John Quinn's previously unbeaten colt The Wow Signal heading the market at 7-4.
Coventry Stakes and Prix Morny winner The Wow Signal was quickly in front in the hands of Frankie Dettori, but was a spent force halfway up the straight and eventually finished tailed off.
The main French hope Full Mast moved up menacingly, but Gleneagles arrived on the scene on the outside of runners.
Joseph O'Brien's mount quickened up to lead, but as he did so he hung slightly across the track, leading to Full Mast and then Territories being squeezed on the inside rail.
After a brief deliberation, the stewards decided to amend the result, promoting Criquette Head-Maarek's Full Mast (11-2) to the number one spot, with Territories second and Gleneagles third.
Head-Maarek said: "That's racing, one horse didn't run straight, he bumped one horse and he bumped another one. Sometimes you need a bit of luck. Mine is still very green and he'll be a very good three-year-old.
"I have to talk to the owners, but I'd think he'll stop now and wait for next year."
Owner Khalid Abdullah's racing manager Teddy Grimthorpe said: "He's a smashing looking horse, he's still quite immature mentally and physically.
"Obviously we would have preferred to win the race outright, but that's the way it is.
"That will be it now for the season."