Eiffel: 1889 worlds fair; head here at dusk for best day & night views (top includes sparkling champagne bar) https://www.toureiffel.paris/en

9:30-23:45

Ticket w/ access lift TOP: 25,50€ 

Link 

⚠️If you take the elevator, the line for the lift is about 3x as long (with reservations) and everyone has to go through security first.