On buying a car in France

What follows is a mostly unedited re-submission of a post I made in 2006 on the now-defunct Assistants-in-France forum. Indeed that year I went through the ordeal of buying a car in France. At the time, as far as I could tell there was no guide like this already out there. By now there may very well be dozens of walkthroughs of the process on the internet. Some of the information in this post is useful, and some of it quaint (“calling cards”!