Eugène Grasset, Georges Callot, Charles Desrosiers, Pierre-George Deraisme, and Charles Jacqueau are among the least-known names in the world of fine jewelry. Yet these men, over a 100-year period that began in the mid–19th century, designed some of the most beautiful and important jewelry produced in the best Paris maisons—think Cartier, Boucheron, Vever. Their relative anonymity derives from the open secret essential to the identity and heritage of these greats: only the house name is stamped on jewelry, not that of the designer. This is hardly unique to France, though as the historical locus of jewelry, the tradition of the anonymous designer began there. Happily, that will change with this exhibition at the Petit Palais. Featuring about 235 sketches and gouache renderings plus 115 pieces of jewelry and other related objects, it’s a quiet but persuasive master class in the art of making jewelry. —Ruth Peltason