In 1943 the Germans introduced the Einheitsanhänger in an attempt to replace the various trailers taken from the civilian market. The Einheitsanhänger were made in 3-ton and 5-ton versions but this one looks lighter so maybe it is only rated for 1.5 tons.
What I am getting at is that there could have been a wide variety of civilian trailers in the 1 to 1.5-ton class “drafted” for military use, just like the heavier trailers. Don’t know if the lighter trailers got replaced with E-trailers or if they continued using them until they fell apart.
This website seems to be some private or semi-private collection:
http://sammlung-eaw.at/anhaenger
The 4th trailer down from the top is similar to, but not identical with, Miniarts version.
http://sammlung-eaw.at/objekt/leichter_wehrmachtsfeldwagen
I wouldn’t be surprised if this trailer turns up in a combo kit with one of Miniarts farm tractors …