The subject is a roulette wheel and the French names that appear on the layout for the 1-18 or 19-36 bets, and the Even or Odd bets. See layout pic below.

But I'm sure you knew that much!

It looks like a fired decorative tile of some sort. And with its small size (a quarter), perhaps a tile that was incorporated into the lid of a jewelry box or something? And with the corners cracked, maybe it was pried up and the corners broken. Just guessing there.

An interesting piece. But I don't think it was used as a plaque would be used.