Comment # 15 on bug 1008248 from Stefan Dirsch

(In reply to Stefan Dirsch from comment #14)
> If you want to change the system's default from French (Switzerland)
> nodeadkeys to deadkeys change the setting in etc/vconsole.conf from
> "ch-de_nodeadkeys"
> to "ch-de".

Of course I've meant "German (Switzerland)". You need to restart the desktop.
If you don't know how to do this, just reboot your machine. Depending on the
desktop you're using this change may only apply to freshly created users,
especially if you changed keyboard setting already in the desktop for existing
users.