If you look closely, there is a Christmas tree behind her. You can see it behind her head, it has white (or yellow) lights and a reflective metallic decoration on top, my guess is that it's a star.
I have another theory on where they are, I think it is an office and it's the office Christmas party.
From 1975 to 1995 my dad worked in a very similar office at a bank. When you entered their section of the floor, there was a large open space where the secretaries sat. There was also chairs and couches where people with appointments could wait. The offices (like my dad's) were arrayed around the outside of the main room (since the execs got the windows, and of course doors on their offices).
If you've ever watched the show Mad Men, the environment is basically the same as in that picture. Secretaries in the common area with just a desk, some chairs for waiting for the execs, and executive offices around the outside so that they could have windows.
Anyway, that's my 2 cents.