Silver ashtrays like that are almost always from the Netherlands or Germany but both countries had sufficiently disciplined hallmarking regulations that I don't think it's from either of those places. I believe it's most likely from Italy (probably Northern Italy) with an unregulated .800 fine mark. Before 5th February 1934 (at which time marks were standardised), Italian silversmiths rarely submitted their pieces for the optional official hallmarking, there was no uniformity of fineness marks, and maker's marks are poorly documented.
The maker's mark looks to me like a stylised conjoined A and R arranged in a triangle, which I don't recognise. Pieces from Arezzo are customarily marked 'AR' but I think the mark here represents the maker's initials rather than being a generic mark for Arezzo.