The Eiffel Tower is lit almost every night, but there are a few exceptions:

* Major maintenance: The tower may be temporarily unlit for maintenance work.

* Special events: Sometimes, the tower's lights are turned off for specific events, like a moment of silence or a special commemoration.

However, the Eiffel Tower is generally lit every night for around 10 minutes every hour, from dusk until 1 am.

It's always a good idea to check the official website or contact the tower directly for the most up-to-date information on lighting schedules.