Policy Maker, fifth under jockey Dominique Boeuf through much of the 1 1/2-mile and 110 yard fixture, and Polish Summer, last in the early going, hooked up less than two furlongs from home and went through the straight together.
Winning trainer Elie Lellouche told the Racing Post, "It was a fair result as he would definitely have won without two taps on the nose."
Boeuf agreed. "It wasn't the leaning which cost us the race but the whip on the horse's face. My partner never gave up and we would have won in a further few strides."
Soumillon shrugged, "I think it is a very harsh decision as we won with something in hand. Anyway it is not the end of the world."
Millenary was fourth, a length behind Craig's Falcon.
The Prix de Meautry Royal Barriere (Fr-III) also ended in surprise with 15-1 chance Blanche winning for jockey Christophe Lemaire.
Blanche held off Zinziberine by three-quarters of a length with Crystal Castle another four lengths behind in third.
Jacques Rossi trains the consistent Blanche, a 4-year-old filly by Loup Soliatire owned by Ecurie Du Sud.