Hello @tkn
You nailed it 
According to the keyboardmap above, the French [AltGr][g] would be the english [AltGr][Shift][b].
It is AltGr+Shift+b.
It's an excellent French blogging software and only alternative to Wordpress
Thanks so much, made my day.
It was not the missing ' which I never noticed honestly, but I spent days looking in the internet about this.
Yes, it was my fault, it was not 0027, but 0146 what the Frenchman wrote... I got totally confused with all combinations