Source: Banque de France, 10 (Dix) Francs, 1940
This is an example of a light and shade watermark. It consists of a head in profile, wearing what appears to be a winged headdress. It might have been intended to portray the Greek god, Hermes.
Additional Book Information
Banque de France, 10 (Dix) Francs, #G.80140, issued on 21 November 1940. The original banknote measures 3-7/16" x 5-3/8" (87mm x 137mm).