Alfred,
Interesting! I'm sure you noted it wasn't an
invention patent but a
design patent. Filed around the same time. (BTW: Wilfert was Bracq's boss and the one who hired him.)
However, if you look up
regular (as opposed to
design) US patent #3,169,793, (filed 1/6/64, issued 2/16/65) you'll find it titled
Motor Vehicle With Concave Top. Inventors?
Bela Barenyi and Paul Bracq. What is interesting with all that is that the design patent you cite clearly has a W113 as its graphic element. The car is in hashed form, while the top--the
design--is solid. On the actual
invention patent, the drawing is some bizarre thing bearing no resemblance to much of anything, save perhaps for an AMC Pacer...(focus on the ROOF, not the CAR) in some kind of push-me pull-you form.
You can search international patents to find those you are interested in by trying this link:
http://ep.espacenet.com/ Some of the earlier patents by Barenyi, probably included in the ones you are looking for, are for a "Passenger Car With Substantially Flat Roof". There's a US patent for that as well, around the same time.
I'm sure that Daimler filed similar in other countries besides France, Germany and US on the same invention, but who knows. A good friend of mine here is an engineer and patent attorney (and whose firm files for some auto companies) and he says when they file today, sometimes it is in
hundreds of countries simultaneously.