Rosengart! Very cool, Aldo!
I haven't made it through all the links you supplied for the marque, but I pulled down my copy of *French Vintage Cars* by John Bolster (c. 1964). There are over 300 French marques from 1918 to the depression that are discussed in the book, and here's what they say of Rosengart:
"The Rosengart was introduced as a French Austin Seven, built under license. Insufficiently rugged for the rough country roads and the pave of the towns, it was replaced by the German Adler front wheel drive design, also built under license. In post-vintage times, a converted Citroen was offered under the name 'Supertraction'."
"Post-vintage times"--1939, for instance. . . .
So . . . in a sense, Richard was right!--it *is* a Citroen, albeit modified (and heavily) by Rosengart. And Steven, while realizing it wasn't a Citroen, was in the ballpark by wondering if it were a modified Peugeot.
If you haven't seen this book, Aldo, I think you'd like it lots. There are currently 13 copies listed at the abebooks.com, the least expensive good copy being one in England running about $26 (sans shipping).
spring green, wi