This interpretation actually isn't too far off. The clothing heavily implies class and Carl Spitzweg, the painter of "Der Antiquar" said about the painting that, "everybody has his throne", meaning that the antiquarian is so absorbed in his old books that he doesn't even notice the upper class ladies with very risque back-decolletés for their time. So while the artist viewed it in a more romantic way (fitting for his time and art style) a more left leaning interpretation is also possible here. Source.