Although there seems to be no crack for the german version out yet, you might just as well use the cracked exe (and nothing but the exe, i.e. arx.exe) from the cracked french version. Get the archive via eDonkey/Overnet through this link:
ed2k://|file|Arx Fatalis-Patch 131.r...b5f65578575bb|
Of course you will have to apply the german update before replacing the executable!
Have fun
Lebon