Put down that macaron! Paris has fallen once more for the slender, seductive, defiantly retro éclair. Two new spots are testing the pastry’s limits, filling and topping them with more than just chocolat and café. In the Marais, jewel-tone glazes and quirky ingredients—caramel popcorn; yuzu—liven up the petite treats from L’Éclair de Génie (pictured). And at L’Atelier de l’Éclair, in hip Montorgueil, sweet éclairs are covered with Nutella and fluffy folds of meringue, while sandwich-like savory versions include—how very French—foie gras with fig confit.