Bad actor with illness collecting royal from German city (7)
I believe the answer is:
hamburg
'german city' is the definition.
(I've seen this before)
'bad actor with illness collecting royal' is the wordplay.
'bad actor' becomes 'ham' (a ham is someone who overacts).
'with' is a charade indicator (letters next to each other).
'illness' becomes 'bug'.
'collecting' indicates putting letters inside.
'royal' becomes 'r' (common abbreviation e.g. RM - Royal Marine).
'bug' enclosing 'r' is 'burg'.
'ham'+'burg'='HAMBURG'
'from' is the link.
(Other definitions for hamburg that I've seen before include "German seaport on the Elbe" , "German state and largest port" , "North German city" , "A meat dish named after the city" , "German city-seaport on the Elbe" .)