Hello
Here are my comments on your chain:
-The style of the links is called maille or maillon gourmette or maille gourmette aplatie to be even more specific. This is a standard and common style of chain, produced in large quantities in many metals (gold, silver, stainless steel). It has no features to distinguish it from other similar chains. You don’t mention the length or weight of this item.
-The marks are stamped at the appropriate locations on the chain and clasp.
-The silver standard mark is either the boar’s head, or the Minerva head mark for items manufactured after 1972. To be absolutely certain of the date of manufacture, you’d need to know the name of the maker and their dates of operation.
-As mentioned earlier, the maker’s mark is in a lozenge shaped reserve, which you show upside down, making it even more difficult to decipher.
-The maker’s symbol appears to be a lighthouse - “un phare.” If you can distinguish the initials on either side of the symbol, it would help in your search for the maker.
-I suggest you search the French Ministry of Culture database for marks registered after 1878 to try to determine the maker.
See:
http://www2.culture.gouv.fr/public/mist ... 4%24%2534PWishing you luck and a bit of patience in your research.
Regards.