This is actually the red envelope in which the paper wallet goes in, and funny enough i already did a design of Euro but with Bitcoin twist for a paper wallet 
you can check it out https://hongbaob.tc/en/papers/144?step=1
This is interesting design you made, but these days I am not comfortable having private keys printed on anything.you can check it out https://hongbaob.tc/en/papers/144?step=1
I know some scary stories from customs in different countries opening packages and envelopes, so that is a security risk.
You should consider adding some alternative for private key, maybe separate sticker with private keys that can be printed locally.