If nothing else, Gaga is all about drama. And she knows what colors work together to make a big and bold statement. Black and white are a huge part of her sets, both on music videos and live concerts. This stark room, highlighted by big lighting, a sexy fireplace, and touches of Victorian lace, appeals to a more sophisticated Gaga style.
You can see some similar fireplaces here:
http://www.europeanhome.com/pages/products/gas-fireplaces/b-vent-fireplaces/milan-60-72.html