One working as judge in German city? (5)
I believe the answer is:
trier
I believe this clue is a double definition.
'one working as judge' is the first definition.
(someone who tries, in the legal sense)
'german city?' is the second definition.
(I've seen this before)
'in' is the link.
(Other definitions for trier that I've seen before include "conscientious type?" , "Test" , "Judge, say" , "Marx's birthplace" , "The Lord loves one, it's said" .)