"If Rimbaud had lived today, he would have been a rock star," said Ann Demeulemeester after her show. And there's a good chance he would have been a Demeulemeester customer. Her broderie anglaise smock, tied at the side with black ribbon, looked just the ticket for the wild-child poet. And perhaps he'd also have been partial to the black cutaway jacket over the elongated waistcoat and pipestem pants.

Spring is now truly the season of the waistcoat—worn underneath a jacket, it's become a heat-wave alternative to the shirt. Demeulemeester showed her waistcoats layered three at a time. Matched with chalk-stripe trousers, there was a formal elegance to the look (the strings of pearls helped, too). Not too formal, mind you. The fact that the clothes were all laundered to the brink of exhaustion meant they were, as the designer put it, "Sophisticated, but in my way."

The same mood was present in the short-over-long silhouette: Extravagantly flowing shirttails were bunched by suspenders under jackets of a normal length; a suggestion of lace leggings hung below the hem of cropped trousers. Aside from those pearls, the mannequins dangled feathers, little skulls, and twiglets around their necks, the kinds of things that, according to the designer, a foraging wild child might find in the woods. That might sound like so much poetry, but Demeulemeester's enduring success proves that such waywardly romantic ideas can pack quite a punch, even in a business as bottom-line pragmatic as fashion.