The only way to have a look at the backstage areas of the Opéra Bastille (unless you have business there) is to take a guided tour. These begin at 5.00 pm on some afternoons from September 1st until July 16th. You can find more details on their website.

Box office at the Opéra Bastille in Paris
Tickets go on sale ten minutes before the tour at window A of the box office, 120 rue de Lyon. Tickets cost 15 Euros (as of 2017), or 11 Euros if you get a reduction.
The tours are in French, basically, but on the tour I took there was a young Asian couple that didn’t understand French, so our guide repeated the main points in English. And he apologized profusely to the three Italian ladies that he couldn’t do it in their language (“the language of opera, after all”).

Beneath the stage at the Opéra Bastille in Paris
We started out by descending six floors (by escalator) to the lowest level, thirty meters below street level.

The lowest level, 30 meters below street level
From the lowest level there are huge elevators to bring things up to the stage.

The workshops
The workshops are huge compared to those in most opera houses I have seen. In fact everything about the Opéra Bastille is huge: the area at ground level is 22,000 square meters, and the total height is eighty meters, including the thirty meters below street level.

Storage area at stage level
This is one of the three storage areas at stage level, with the same dimensions as the main stage.

Stage set for Wagner’s Lohengrin
This part of the stage set for Wagner’s Lohengrin was set up and ready for use on the following evening. All the performances of Lohengrin were sold out, by the way, even though the large hall of the Opéra Bastille seats 2703 people.
My photos in this post are from 2006 and 2007. I revised the text in 2017.
See more posts on the Bastille.
See more posts on operas in Paris.