The man look became big in ladies’ attire of the 1930’s at first for business wear to ‘indicate seriousness of intent’ (Stella Blum, Everyday Fashions of the Thirties), but also filtered into other ladies' day and evening wear. The man look never goes out of style and even if it did, my wardrobe would still include it!
Pattern SE30-1210 is a super rare pattern which is the earliest ladies’ street trouser pattern I have ever found.
I think the rendered model in the center of the pattern art resembles Marlene Dietrich (who alongside Katharine Hepburn popularized ladies’ wide leg trousers during this decade).
Click here to see pieces a customer made from the pattern. As Nick indicates in his entry, the top-stitching at each trouser pocket is a distinctly German detail in men's tailoring.