The July Cup hero was well fancied to double his Group One tally at Deauville, but was beaten just under two lengths into third by the prolific Marianafoot.
Starman disappointed in a soft ground Qipco British Champions Sprint at Ascot last season, while he was taken out of the Diamond Jubilee at the Royal meeting on account of testing conditions.
Trainer Ed Walker believes a combination of the easy surface and an extended trip of six and a half furlongs proved his stable star's undoing in France, but he has no regrets about allowing him to take his chance.
He said: "I think we were right to run. The ground wasn't as bad as it was at Ascot either on Champions Day or at Royal Ascot, when we took him out.
"We nearly got away with it. At the six-furlong pole he was nearly the winner. He came there to win his race and didn't get home.
"I'm very proud of him. He ran a massive race and was very brave. He's genuine and talented and the ground just blunted his speed and put more of an emphasis on stamina.
"He was beaten by a couple of horses that have got very good form over further.
"I think he lost nothing in defeat and credit to David Ward (owner) for being brave enough to give it a shot."
Walker is now praying for drying weather ahead of the Haydock showpiece on September 4.
"We live to fight another day and when we get him back on proper fast ground we'll see his true colours again," the trainer added.
"We've had so much rain we're surely due a dry spell. We'll aim for Haydock and see how we go."