Private home or a set?

Would anyone know anything about the mansion where this movie was shot, or anything about the interiors of it? It's been a very long time since I saw this movie. The first time I saw it, I really enjoyed it ... and I would like to see it again. Bette was great. The mansion of her twin sister was elaborate as I remember the movie. Does anyone have an idea of the location of the house or the old bar where she had originally worked? I guess they were sets, but I think that I've seen that house in other of her movies but it may have been in another classic movie. I had researched it, but have run into only dead ends. Thanks for any help.