France 56th floor of Tour Montparnasse, Paris

Tour Montparnasse is a skyscraper in the center of Paris with an amazing view over the city. The current price to get up there is about 15€ for adults. When you are at the top of the building you have the option to shoot from the upper observation deck (panoramic terrace) or to take your photos from the 56th floor. In my opinion the second choice is the better one, although you have to shoot through a glas window, because you can see much more from the city itself just infront of Tour Montparnasse.

Please be aware that the Eiffel Tower at night is protected by Copyright Tour Eiffel - Illuminations Pierre Bideau. You may use those photos for yourself, but not in a commercial context. I am not sure which size of the Eiffel Tower is relevant for this copyright, because if it's only seen in your photos as props you may be fine, even at night. Please make sure to check these things for yourself before using night photos from Paris!

Annotation: I removed the Eiffel Tower from this image until I've got an answer from the SETE if I am allowed to use it on this website or not.

Especially when it's getting dark you have to make sure, that there are no reflections in your photos. Use a dark scarf or something like that around your lens to prevent reflections from inside.

There are a lot of Metro stations nearby like "Montparnasse - Bienvenüe" or you can get there by train to "Gare Montparnasse", which is just in front of the building.