PARIS — Yves Saint Laurent is back. After a month-long battle with double pneumonia, the designer is back in his atelier and promising a collection that’s “pure and all about simplicity.” Rather dapper in a sharp double-breasted dark suit, white shirt and blue tie, Yves, sipping a Coke Light, was putting the last-minute touches on the collection he will present today.

“Fashion was too heavy before,” he said. “Now that’s demode. There’s a return to elegance — not tight, but flou. It’s all very flou.” Along with his impeccably cut pantsuits with men’s jackets, Yves promises an all-white series — classic short suits and dresses for day in savory silk shantung and long A-line sheaths and dreamy ballgowns for evening. He’s also keeping details to a minimum. “It’s the essence of Yves Saint Laurent, our roots,” said Loulou Klossowski.