Image credit the Guggenheim Museum, Paris Through the Window, Marc Chagall, 1913, oil on canvas, 52" x 55", held by the Guggenheim Museau, New York.
This image is multifaceted, and the more you look at it, the more you see.
My initial impression--from a distance--was that the cat held center stage (naturally!). But closer up, the cat clearly has a human face. But then you note the Eiffel Tower, and the very large window pane on the left.
And what about the two-faced individual on the right? Two-faced--it's almost too easy of a stereotype. And the disturbing pair of bodies floating above the two-faced guy could be the focal point of the cat's attention.
So back to the kitty. The poor creature seems sad or in distress. In a location where Paris is spread out before you, distress seems to be the last emotion one would want to have. Perhaps the kitty knows it's a house cat, forever inside-bound, fated only to ever see Paris through the window...and thus the title.