I've a problem successfully performing the C-M-\ combination on my azerty keyboard.
The main issue is that to hit \ I need to hold down alt gr, and this seems to mess up the whole thing. I'd be interested to know what's the classical answer to this problem, if there's one that's not 'rebind the command'
And other azerty related tips would interest me too.
Usually the answer is to type ESC C-\ (all M-foo bindings can be reached by hitting ESC foo instead), which is usually a bit easier, tho depending on your keyboard it can still be tricky.