OK, here's a tough one. When you go to an opening for a famous fashion photographer like Patrick Demarchelier, where every model in town has turned up, do you look at the art on the walls or the hotties in the halls? "I'm quizzing people to see who is here for him and who isn't," said Jessica Stam. Her oh-so-scientific findings? Some guests, like Dita Von Teese and Emma Watson, had done a dutiful lap around the multilevel exhibit, Images et Mode au Petit Palais. Others, though, had skipped any aesthetic pretenses and gotten right down to the pretty people-watching, which was epic even by Paris fashion week standards. But while the photos may have taken a backseat to the merrymaking, Demarchelier himself was every bit the center of attention. "He is the best," said Natalia Vodianova, standing in front of a series of herself that appears in this month's Vogue. "He really makes you feel beautiful and sexy and like a woman. Even when he's not taking your picture."

— Derek Blasberg