This is a notable listing - so good to see on Ebay. The Germans produced 12 different diecut tiaras, or diadems, during the 1920s. Although packaged as a set, as illustrated by the envelope present, they more often were sold individually, accounting for their varied rarity and value. On page 188 of my newly published third edition, the seated cat is valued at $275. The envelope is exceptionally rare. The last one listed had with it about 6 tiaras and fetched several thousand dollars.
01/12 Update: This listing ended at $1,331.77, a completely unsustainable result. The tiara typically fetches $275, so is the tattered sleeve worth over a thousand bucks? I don't think so...
