The pieces have been exhibited in several locations; mostly attributed to Casino Elysee Palace in Vichy because of the "CEP" on the overlay.

They have also been reported as inventory of another French casino (notes somewhere in TCB archives), but I do not recall, except that their name had the monogram/initials CEP.

I've also heard BG was the manufacturer (1925-1931).

The "CEP" is still unknown.

There are similar Monaco pieces with metal overlays.