Originally, Paris would have hosted a race of the World Grand Prix, but it was pulled out of the story because it was too much story to tell. However, it appears in the Nintendo DS version of Cars 2: The Video Game.
Lighting director Sharon Calahan paid homage to Ratatouille, by using a similar soft warm broken lighting approach. To add authenticity, Julien Schreyer, the master lighting artist who worked on those Cars 2 scenes, is actually from Paris and had worked on Ratatouille as well.
Notre Dame Cathedral is adorned with 24 "car-goyle" statues and flying buttresses in the shape of exhaust pipes.
The top of the Eiffel Tower is the shape of a 1937 spark plug; its base contains the features of a wire wheel.
The Pont des Arts is constructed with automobile leaf springs – a type of spring used in car suspensions.
There is a longstanding Pont des Arts custom wherein couples attach a padlock to the railing and throw the key in the river, sealing their love forever. If you look closely at the Pont des Arts in Cars 2, you can indeed see padlocks on the railing.
John Lasseter and his wife, Nancy, were once told during a visit to Paris that couples are supposed to kiss when they cross the Pont des Arts. This tip made it into Cars 2, where two cars are seen kissing on that bridge.