Accidental, of course
Everything was in motion: The bus, other vehicles, the guy pushing the cart, the girl trying to shield her head from the rain- even the guy in the red jacket, who seems the most still thing in the frame.
There is something about this photo that I've liked since I first saw it on the tiny LCD on my camera. The colors, the motion blur, and the- mostly accidental- composition. (I did take this out of a moving bus window!)
This sort of symbolizes Paris at rush hour. And we were in the middle of it, on our way back to Terminus Nord to catch the Eurostar back to London.