Christophe Landon definitely makes bows and instruments, I have personally seen him doing both. Contact him and he will illuminate you on his training, which is thorough. Christophe is a very accomplished maker and copyist.
I know this original post is a few years old but just in case you never got to the bottom of your brand mystery this may help.Here is a clear example of the brand on your bow. This photo comes from a JW Knopf.