Need to find a Coulaux catalogue, I guess. In the meantime, this remains a fermoir until proven otherwise. I’ve got other big chisels.Nosban also defines the fermoir back in the early 1800s (merci, Nico). At that point the blades were made of three layers fused together; two iron on the outsides and a steel in the middle for the edge.That further suggests to me that a true fermoir would have tops/bottoms equally tapered like daggers, not sided differently.¯\_(ツ)_/¯