The rooftop overlooks the city of Paris. There is ...

The rooftop overlooks the city of Paris. There is no Ferris wheel, but it's free. You can also go by direct elevator.
The best places to see Paris are Montmartre Hill, Galeries Lafayette, Eiffel Tower and Montparnasse Tower, but this is the best place. Anyway, it's free.
Since it is a department store, there is also a toilet. Immediately after entering the building, there is a toilet near the shoe department in the basement, but it is a long line for Madame. The accompanying Chinese men occupy the try-on chairs at the shoe department.
The other is a toilet on the floor of the 6th floor food court. This is a large room with waiting sofas and USB charging.