Image source: AZERTY - Wikipedia.
@mazeyrat, a quick web search reveals that the non-English keyboard layouts have been a problem in other softwares’ keyboard shortcuts too. The problem appears to be that you’re having to use the Shift key and this messes up the keycodes. (I can’t remember how exactly this works but the character is returned along with the status of the Ctrl, Shift and Alt keys.)
Some posts suggest that if you have a number keypad that Ctrl-/ or Ctrl-÷ or if you have a laptop with Fn numeric keyboard try Fn-Ctrl-/. (The older Dell laptops had this and it was super. I don’t know why they discontinued it.)