This thread really points out the need for a supermarket directly underneath the T.E. That space is being wasted now, and it's long past time to put it to good use.

There's certainly enough space, not just for a supermarket, but for a decent-sized upscale mall. Maybe some of the shops from Forum des Halles can move there.

And for those bleeding hearts who want art instead of shopping, how about a nice trompe d'oeil under the Arc de Triomphe?