It is a
jeton de presence, a silver medal of equivalent weight to a (then) circulating coin.These jetons were commonly used in the French Insurance industry, among others, as a form of remuneration for Directors. Nothing so grubby as money changed hands, but they had financial value. It is not uncommon to see these with a fair degree of circulation wear. Prices range from $25 - 100 depending on rarity.
This:
http://www.coinpeople.com/index.php...-lassurance/gives a good explanation and illustrates many types, including some of my own.