Crazy finish set up in German city (7)
I believe the answer is:
potsdam
'german city' is the definition.
(Potsdam is a city in Germany)
'crazy finish set up' is the wordplay.
'crazy' becomes 'mad' (synonyms).
'finish' becomes 'stop' (synonyms).
'set up' says the letters should be written backwards (in a down clue, letters go up).
'mad'+'stop'='madstop'
'madstop' reversed gives 'POTSDAM'.
'in' acts as a link.
(Other definitions for potsdam that I've seen before include "German city" , "conference centre" , "where conference was held" , "1945 conference location" , "conference city" .)