I figured out that by disabling
Settings > Privatsphäre (privacy) > IP-Adressen anonymisieren
the cities are shown.
The first option “Anonymisiere IP-Adressen” can still be enabled, though.
However, the naming of both options is confusing and should be more distinct.
Also the current explanation “By enabling this option, you cannot recover the IP addresses in the future to find out location information” is misleading, since it gives the impression that one could still resolve it in the present or at least once.
