Chalk drawing good 20/30s

Beautiful drawing of a girl/woman with mat from the 20/30s. In my opinion it is a chalk drawing. The image is taken good from Rudolph Behrendt who then made his reputation in Berlin of portrait painting in oil, chalk and watercolor. He had at the time in Berlin in the Köpenicker str. 110 his Atellier. MAT dimensions: 49 x 60 cm, frame: 34 x 44 cm.