The rifle is an upgrade of the Sauer & Sohn, Suhl model 1936. A very similar rifle is shown in Jim Cate's S&S book, page 177.
Here are some photos of my own standard grade S&S M36 in 7x57R, proofed March 1937. Sure, it is not a collectors item any more, but a good break-open working rifle. My grandfather bought it when new. In 1945 he put it in a wooden box and buried it in a fox burrow out in the woods. When it was unearthed some years later, it showed some outside rusting on the left side and a ruined stock, a fate it shared with many guns that stayed in Germany post-WW2. Grandpa had it restocked by some local "gunsmith" and a scope fitted in some way to the existing bases, much too high and too far back. That "gunsmith" produced an awful stock shape, apparently influenced by then-current target rifle style, with a 3 by 3" beavertail foreend. After I inherited the rifle 35 years ago, in due time I trimmed down that clumsy stock to something at least resembling a proper single-shot stock. I replaced the defective ds trigger with a single one, the shaky claw mounts with old style Warne bases and rings and mounted a 1960s vintage 4x Hensoldt "Diasta" scope. No, it isn't for sale!