score:7
My guess is that's a head of wild hog - French hallmark for 800/1000 silver fineness used for small objects from May 1838
Here is a page about french hallmarking system on silvercollection.it. Look for "Hallmarks from 10 May 1838".
Another page from wineantique dedicated to silver standards.
French 800 was guaranteed by the Minerve 2. The Minerve surrounds were the same but now a 2 appeared just below her chin. Small 800 items were marked with a crab or warthog's head.
UPDATE: Found the discussion of another carnet de bal with similar mark recognized as a silver standard hallmark:
Marked on the front with the head of a wild boar (French hallmark for silver fineness of 800/1000, introduced for small silver articles on 10th May, 1838).