The answer is that the first car in the photo is not–as suggested by the Editor–a Stoewer, but definitely a Protos, built by the Siemens-Schluckert works at Berlin.
The shape of the body suggests that is was not a pre-war Protos, but a car built between 1920 and 1924; i.e. the type “C” with a 2,596-c.c. four cylinder s.v. engine of 30 b.h.p. at 1,800 r.p.m. Protos was a middle-size factory which never built any real “hot” cars and the type “C” had a top speed of approx. 48 m.p.h. The NAG bought the Protos works in 1926 and soon afterwards production ceased . . . with the exception of lorries, which have been built until the early thirties with “NAG-Protos” on the radiator.
Nettelstedt. Erwin Tragatsch.