Looks like the tiny storage shacks the Germans have for the gardens.
I have a “garden “ shack complex in the b/y. Summed up it’s about 10’ x 10’.
The gardens (groups of small parcels of land on the outskirts of town, next to the railroad tracks, or otherwise away from "ordinary" human habitations) are called Schrebergärten (Plural). Moritz Schreber was the man who popularized them.
The sheds are called Schrebergartenhäuser.
I am always amused when I encounter American tourists or even soldiers stationed here who assume that they are normal human habitations for "poor people."
Regards,