
Keep Galeries Lafayette Rooftop only when it outranks a half-day elsewhere.
Allow 30–45 min.
Two payoffs in one stop: the spectacular stained-glass dome over the shop floor, then a free rooftop terrace with the Opéra, Eiffel and Sacré-Cœur on the horizon. It's a department store, so it's busy and commercial, but the view costs nothing.