Take in a fabulous view of eastern Paris from this rooftop bar, which has been so successful it has spawned a passel of other high-altitude nightspots on top of buildings in the Marais, Buttes Chaumont, and even, in summer, the roof of the Gare de l'Est (check website for locations). Sip a cocktail on an outdoor sofa and gaze at the Sacré-Coeur, or flirt at the tented bar. It's popular so reserve at least a week ahead.