***** revived thread from 2015 ***** Below is a link to research published on the cinderella and the document posted by the OP.
Conclusion: the document is a philatelic fantasy dating to somewhere between 1965 and 2013 and contains a lot of nonsense.
The seal, may be a real advertising seal dating to the late nineteenth century. It may be a reprint of such, but it, as well, could be a fantasy item. It, certainly, is not a private carrier stamp. Nor does it have anything to do with the German occupation of Belgium.
https://www.pelteret.net/content/00...nderella.pdf