Between Avenue Montaigne and the Rue du Faubourg Saint-Honoré, a short walk from the Champs-Elysées, the Spa de La Réserve is the exclusive purveyor in Paris of "cosmeceutical" treatments from Nescens-Swiss Anti-aging Science. The new 4-hour Be Slim ritual includes your own personalized coach, a hammam, an in-depth massage, and a vegetarian wellness breakfast, gluten and lactose free, concocted by star-rated Chef Jérôme Blanctel. 400 €. Spa de La Réserve, 42 avenue Gabriel, Paris 8 (01 58 36 60 60).