PARIS — It was a big milestone, and an unusual moment for a major Paris house. Emanuel Ungaro transferred responsibility for his ready-to-wear collection to his creative director Giambattista Valli, announcing the move shortly before the house’s spring show. Valli’s agenda is clearly to simplify the Ungaro look, and, in this debut collection, he toned down some of the wild mixes. But he captured the sensual spirit his mentor is known for in provocative linen looks and soft pantsuits. Here, another example: a racy chiffon dress with Art Deco detailing.