The Kreuzaxt was replaced a very longtime ago by a development of it. Some time along the line, they removed the wooden handle (but left the socket) and also the mortising chisel was removed. We are left with a tool known as Stossaxt or Stichaxt, which is today a very very common tool.
Thank you. That was the name I was trying to remember earlier. In French it is known as a demi-bisaiguë. I get the impression that it's less common in France (certainly it's more common the closer you get to the German border), but it's well-known enough that you can buy them fairly easily.
Edit to add (didn't finish reading the whole thread!):
Jay: The bisaiguë is not a particularly common tool here. While I'm sure that all carpenters are aware of it, I don't image that wery many use it still (Not least of all because most carpentry work here (at least in Normandy) is limited to installing industrial trusses onto concrete block houses. More call for a nail gun than traditionally mortising tools.
D L Bahler: Interesting idea. I assumed (largely from the French names) that the Bisaiguë evolved directly from the Kreuzaxt, and that the demi-bisaiguë came about from people only needing the one end. I've not researched this at all so I speak from guess-work, not historical understanding.
