It is a cover-up used by a decoration studio, as it clearly covers the original producer's marks, e.g. those of the Retsch factory in Wunsiedel.

M170101a
"BAVARIA" and "GERMANY" flanking a crown set above "MHM", "HANDARBEIT" and "22 KARAT GOLD" (type 1).

M170101b
"BAVARIA" and "GERMANY" flanking a crown set above "MHM", "HANDARBEIT" and "22 KARAT GOLD" (type 2).