A black pantsuit, paired with a shiny black miniaturized violin case for a bag: That's the news at Rochas. This was the first time Olivier Theyskens has shown a pair of trousers on this runway, marking another small step forward in his unhurried nurturing of the brand. With their slightly crumpled surfaces—as if dried after a sprinkling of rain—these pantsuits belong, for Theyskens, to the same poetic vision that embraces his long gowns, skirts, and high-neck blouses. "I felt it was time to do them," he said. "But I treated them with a flou, like I work the rest."

"The rest" related back to the attenuated, romantic Edwardian silhouette that appeared in his winter collection. This season, the impressionistic sources of his precious dresses were Claude Monet's paintings of his garden at Giverny—and faded sepia photographs of the lace-collared blouses, small jackets, and long skirts worn by the sculptor Camille Claudel, the wildly beautiful young lover and muse of Auguste Rodin.

The most-obvious clues to the designer's elusive references were water lily embroideries blossoming on gowns, but he executed his ideas with such subtlety that the chiffon surfaces of a deep-blue dress and the streaming flare of a pleated train seemed to flow like water. As for Claudel, she had to be the moving spirit behind the pale, off-white and mushroom-tinted dresses and the ruffled lace capelet-sleeve gown that was the collection's showstopper.

Theyskens is more one to hint than hammer at a theme, though. All one really needs to glean from this season is that it's a gentle, lingering development of the ideas of a designer who resists external pressures to rush headlong from one thing to the next.