This photo, from 1907, was probably the first color photo of a car. It was photographed by Jean-Baptiste Tournassoud using the Autochrome Lumiar process. The Lumière brothers patented the process in 1903 and was the most used for color photographic records until the mid 30's. The car seems to be a picture of Peugeot 116.
From the archives of Nik, http://carrosantigos.wordpress.com/2008/07/18/a-primeira-foto-colorida-de-um-carro/ Nik finds the coolest stuff!