This is an Enamel sign I believe from Bulgaria
This is a great enamel telephone sign. Judging by the type of handset I would say dates from the 1940s. As you can see the design is very nice. It has some damage where it was screwed through the two fixing hole and a little rusting around the edge but nothing over the main display parts. It is convex in shape and the diameter is 15 inches or 38 Centimetres.