This is known as Young Noblewoman in a Salon, by the French artist Felix Armand Huellant, about whom all I know is that he was born in 1834. I've also seen an alternative title, Contemplation. That seems right -- she is certainly contemplating something, though whether it's the book she's obviously abandoned or something else is hard to say. To me she seems to have a distinctly naughty look on her face, which makes me suspect that her thoughts have strayed both from the book and from her rather dull-looking older husband, and onto her gorgeous young lover. But I could be quite wrong. Nice dress, anyway.