What does “a study in olfactory desire” smell like? If you ask Le Premier Parfum’s Pauline Rochas and Carole Beaupré, it has everything to do with a deeply compelling, head-turning blend of ylang ylang, sandalwood, patchouli, and resinous labdanum, among other ingredients, that produces an instant, almost obsessive “what is that?” reaction from anyone within sniffing range.