Though it has been suggested maybe Romania (Constanta) in a very honest way from within Romania, I still do not find anything except another shape plaque with that also only being found in Romania.

From what I am reading, it appears the gaming operation was not ongoing after World War I, and there are no interior photos showing a gaming casino in Constanta... though many exterior are found, which is not the case with another casino back then in Romania.

Not to be confused with a modern casino in Constanta.