These are the German parody forgeries of the 1937 Great Britain King George VI issues.
Changes to the design include the Star of David atop the crown at top center, and a hammer and sickle inserted in the flower at top left and in place of the pence symbol.
These issues were also overprinted (MiNr. 9-14) in many different varieties.
For more on there issues, see Propaganda and Espionage Philately, by SGM Herbert A. Friedman (Ret.).