At least I thought this was a mass joke on several critic accounts, but now I hear rumors of the Eiffel Tower being seen destroyed in one of the Earth Kingdom villages. If true, this means the movie has officially separated itself from the series and could very much be forgotten from history.
I also found an image of what parts might be seen in the movie.
There was sighting of the ruined tower somewhere in the Earth Kingdom scenes. Also, plenty of critics, beside Rodger Ebert, say that the movie takes place in a post-apocalyptic world. I do not remember, but at the beginning. Did Katara say the world was once inhabited with cities?