
I know no-oooothing, as the saying goes, but this is my tuppence worth.
I'm sure, at least in the uk, that there are laws about defacing legal tender, so if that applies to France too, this should have been made after the coins ceased to be legal tender, unless it doesn't matter about french coins over here.
The tools look to be made of steel, perhaps it is a watch fob - or a key-ring?