Based on the style of a women's dress pattern that was part of the same lot, my guess is the early 1920s.
Since I have no knowledge of German, I've relied on Google Translate to help me out here, so this post will be of a somewhat minimalist nature.
This is, apparently, a "sculptor's coat," which may be as generic a term as "artist's smock," or "shop coat." Available in sizes for both men and young men, this is a nice example of its kind. Gathering the fronts and back into a yoke provides some additional ease, so that the coat could be worn over a suit jacket or a heavy sweater. And you can't go wrong with four pockets!
Ullstein Verlag, a large publishing house based in Berlin, published Die Dame, a ladies magazine, and this line of home sewing patterns - a business model similar to that of McCall.
It's easy to imagine this smock being worn in the studios at the Bauhaus.
