The closest I came to anything with the exact two words was an improvement in Hungary during the late-1800's, where several hotels were being built in a spa resort area and the mention that the casino should be completed shortly... Then, there is no more information about the casino.

I have completely discounted anything in France since there isn't anything "Thermal" with this monogram on paper, façade, gate or chips... and I have been searching for close to 30 years in articles, books and so on. Nothing.