Label cities currently occupied another civilization

[Jens Herrmann]

I have a feature request for a new label/symbol on the city banner.

Actually it is a stupid work to figure out wich city is occupied by another civilisation.
You have to go through all gossip again or look up if a cityname belongs to the actual owner.
A label would be nice for using a relief Casus Belli or increase diplomatic relations to the original owner.