Just as Eugenie Niarchos and Gaia Repossi were zipping themselves into their Balmain gowns for a party the two were hosting for their newest jewelry collaboration under the Repossi label, an immense thunderstorm clobbered down upon Paris. Good thing, then, that they had chosen to have the fête at the Ritz, that gilded, chintzed, and plush fortress on the Place Vendôme, where little nuisances like Mother Nature rarely seem to intrude. The youngest generation of some familiar international families—Andrea Casiraghi, Tatiana Santo Domingo, Vladimir and Julia Restoin-Roitfeld—mingled with those with well-known last names from America, including Mary-Kate Olsen and all three Traina sisters, who had brought their father with them. Providing some grit in the oyster were art world-ers like Nate Lowman and Aaron Young. They wandered through the mirrored salons along with fashion figures like Anna Dello Russo and Karl Lagerfeld, the latter of whom photographed Niarchos and Repossi for beautiful portraits displayed throughout the party. (Lagerfeld also took some pictures of current boy toy Baptiste Giabiconi wearing nothing but the whole collection, but for some reason those images weren't as prominently placed.)

Lest anyone forget that the point of the party was the gold and diamonds, the duo's finger-covering rings, oversize bracelets, and statement earrings were on display in glass cases in the back. And though many may think Niarchos' skills lie primarily in whipping up pieces for her gaggle of chic girlfriends, she turned out to be quite the saleswoman, guiding prospective buyers, like the Japanese footballer turned fashion icon Hidetoshi Nakata, through her wares. This wasn't strictly a shopping event, but more than one girl was scheming about how to go home with some bling. "This is my favorite piece of jewelry I've ever worn," Margherita Missoni said of a rose gold earring that hooked onto the ear—no piercing necessary—and decorated the whole lobe with diamonds. "I'm going to try and get [Ritz owner] Mr. Al Fayed to buy it for me."

— Derek Blasberg