It's the Peugeot 402! Thank you so much kegare. This has been driving me crazy. You're a gentleman and a scholar.

http://www.youtube.com/watch?v=XPA1m51cc24&t=5m20s

http://www.imcdb.org/vehicles_make-Peugeot_model-402+L+Taxi.html

This Tintin movie: http://www.imcdb.org/movie_983193-The-Adventures-of-Tintin.html ?

If you don't see the car there maybe some kind soul will add the first movie you mention to the database and find it there.

You are probably talking about the Peugeot 402.

I've been trying to determine what the car the taxi is that Don Ameche drives in the 1939 movie "Midnight" with Claudette Colbert. I recently saw the same car in the Tintin movie. It is the scene where Tintin is pursuing the pickpocket and is almost hit by several cars in the street.
I have not been able to find any images of it online, but that's mostly because I'm at a loss of how to search correctly for it.
Any ideas?