~~~ 90 mm decals that looked like those.

I don't know what they were used for, but they came in special packets purchased at the reception that also included special DM5 (unmarked) jetons to be used at instructional Roulette during certain hours of the day... The jetons were in little felt bags.

I think I still have them from Baden-Baden, Bad Neuenahr and Durkheim... (The BADED-BADEN jetons were the nicest; gold flake with a red lunette and black B w/o denom).