Serge Gainsbourg is the renewable resource of French menswear, an ever-charged battery of inspiration. For Spring, Olivier Rousteing availed himself of the volts. He loved Gainsbourg's shuffling way with a dancer's shoe, the thrown-on jacket, the essential Frenchness of it all.

But source material mutates in the making. The essential elegance of the slip-on ballerino flats Rousteing designed was undeniable. (For a 2013 touch, he threw monk straps on a few.) And nautical details like marinière stripes and sailors' appliquéd badges remained, in homage to one of Gainsbourg's preferred playgrounds, Saint-Tropez. But the main thrust of the collection came from the clash of workers' overalls and mechanics' jumpsuits worn with tweed jackets that had a whiff of vintage Chanel. Only Coco never wove hers with metal chains the size of bike locks, or, for that matter, appliquéd denim on denim to create houndstooth motifs. Whatever the original inspirations, the final product was squarely Rousteing's. "It's more me," he said, than any men's collection he's done.