Sosie, sent off as favorite when fourth in last year's Prix de l'Arc de Triomphe (G1), returned to action with victory in the Prix Ganay (G1) at ParisLongchamp April 27.
Trained by Andre Fabre, Sosie was beaten four and a quarter lengths behind Bluestocking in the Arc, but showed a good turn of foot early in the straight to win the first group 1 of the year in Europe.
Map Of Stars, impressive when winning the Prix d'Harcourt (G2) on his return three weeks ago, finished like a train under Mickael Barzalona but found the winning post coming just too soon.
Settled in fourth under Maxime Guyon, Sosie was well positioned to strike as the sprint for home started, and, with winning form over further, he was always going to be hard to peg back after striking the front.
"I'm delighted," said Fabre. "It was his first race of the season, and the distance was a little bit short for him, but he had the class to win. He's improved with age, and we can now consider races like the King George (at Ascot).
"He prefers good ground and wouldn't handle it too soft, but with age, horses get stronger."
In contrast to the winner, Map Of Stars had to come from the back and was forced to make his challenge down the wide outside, looking a little unlucky as he chased down Sosie on the run to the line.
The Karl Burke-trained Royal Rhyme finished third, with Joseph O'Brien's Al Riffa back in fourth.
