Everything?

Here it goes...
-The floor is pretty non-realistic (imho), unless this is an "art" thingy.I guess you could texture the whole surface with planks/boards, or model the few planks/boards and texture them individually.
-The almost inivsible glass wall is a mystery.
-A little exciting with the light seen in the upper left corner (kind of a detail)
-It looks like the carpenter had been exceptionally apt at setting up on the walls, a few "trims" (?) between the floor-wall-ceiling would add some "realism" I think
-I think the "cloth" looks pretty good (you are ahead of me on that one!)

And you can always add various details to spice things up.

Oh a last thing, I'm not sure how big a person is in this scene, but I'd say that the "chairs" or the seats (I cant think of any other word for it at this time) are a bit (a little) too wide.