It looks like it is not in the newest group, but I can't say when was it produced. It seems the fabrication of these axes is more complex than I learned, they weren't exclusively made in the Basque Country, they also were produced in certain zones of France (surely near of or in the Biscayne gulf) and in some American French zones (Quebeq at least, no quantity and time lapse information). My thought is that this is a early fur trade era Basque region design Biscayne axe, but I can't exactly say were it was done. will be better if you contact a especialist.
300Six is right, this axe eye has had a hard pounding. It originally was oval, I think this type of axe usage originated today's standard polled axe, more balanced head and the almost total widespread of the wedged handle was a subproduct of it.
It seems the top zone of the bit has been the most used and grinded, take care when you sharpen it, could not have much steel here compared with other zones.