The Eiffel tower may be considered the most famous view spot of Paris, but I personally recommend the Montparnasse Tour.

There is always a long queue to go up the Eiffel Tower, but you can go up the Montparnasse Tower without having to wait in line. Also, you cannot view the lit-up Eiffel Tower when you’re actually in the tower itself, but you can outlook the beautiful illumination of Eiffel Tower from Montparnasse Tower.

There is an indoor observatory on the 59th floor, and the guests can access the roof deck from here. There is no additional fee to get to the rooftop, and can go in and out of them as many times as they wish.

After purchasing your ticket, there is a security check where the security guards check your belongings. I had a middle size tripod with me, but I was able to enter without any trouble.

The entrance may be difficult to locate, but the 'P' mark on the map on this website is the entrance. It is located on ground level, so if you are coming here by subway, please get to the ground level first.