With Atom Editor, on a Qwerty Keyboard, the combination Shift + Ctrl + Alt + [ allows you to fold all identation, and Shift + Ctrl + Alt + [ to unfold.
This combination is impossible on an Azerty Keyboard as [ can only be accessed with the AltGr key which cannot be used along with Alt Key.
Do you know how to fold/unfold lines in Atom Editor on an Azerty Keyboard ?
The Atom Flight Manual includes instructions on how to set new keybindings. Atom doesn't have an ability to distinguish between keyboards as far as I know, so if a character like
[is inaccessible with the rest of the keybinding, then you should definitely define your own.