The painting is classic art - Le Boudoir from like the 1770's. If I had to guess (which I am) I'd say the hidden cabinet is early 20th C. But people still have these in their houses today. Do a search on "hidden cabinet" and you'll find lots of DIY projects to make them.
I agree with Matt; it looks to be early 20th century. The painting is a reproduction of Pierre Maleuvre work. I've always thought these hidden cabinets were interesting.