As said before, the lighting could be improved (but I believe you already practiced that)
To be honest, it took me a couple of seconds to realise this is finished. That back wall looks way more realistic than the pieces of wall in the front, so I thought you still had to texture that (no offence)

an extra hint, as far as I know, marble texture usually doesn't continues from tile to tile, so perhaps you could try to change that
Overall, nice model and scene, but it can (pretty) easily be improved, good luck