This base was commonly known as "Marchal", and as you properly says it comes from France.
These bases were very common in many European countries up to mid 60's, but in the three contact version, where the brass sleeve was connected to the common lead-in wire of two filament system. The tin contacts fitted on the vitrite insulator were connected to each individual filament for long and short range light respectively.
Most french cars manufactured until mid 60's, as Citroen, Renault, Peugeot, etc. were fitted with such based lamps.
A french car (also manufactured here) that was very popular here in Spain, the "Citroen 2CV", used these lamps until the arriving of "European Unified Base System", mainly in 6 volt version.
But not only was used for cars, but for trucks too.
Here are a curious sample from my collection, a Spanish made "Wagner" 24 volts, 45/45 watts? rated lamp that has a very unusual bi-colour bulb (yellow and clear) for truck use, that are fitted with the "Marchal" three contact base too.
Because the point of view, at the picture cannot be well seen the two contact structure at the base of the cap, however this is a genuine three contact Marchal.
Also, I have a huge couple of another "Marchal" lamps too, because my father was a car electrician, and he let me to play with them when I was a child, so I preserved lots of them that he has as a surplus.
Many years ago, in Europe were also used another base types, as the German "Bosch" bayonet, in wich only was two plane and rectangular shaped pins, unequally sized to avoid any assembling mistake.
However, the three contact Marchal cap is equivalent to B22d British three pins base used for discharge lamps instead the regular two prongs version found on incandescent ones.
When I will get my website online again, I will include a new section specially dedicated to these automotive "gems".
Best regards.
M. Gonz?lez.
