Wow, great responses everybody. I'm surprised this little filly attracted so much attention.
Planitarium, it's too small and thin to be a coaster. Definitely a label.
In fact I think I think you may be dead on with the cigarette lead.
Here's another Roxy sign I found on a German website selling tobacco advertising.

And when I look on the back of this little baby (the sticker, not the sign) there is remnants of a yellowish paper with threads running through it, so I'm thinking it may have been a sticker to seal a cigarette package shut.
Nice work, thanks!