Good French name for German city (4)
I believe the answer is:
bonn
'german city' is the definition.
(city in Germany)
'good french name' is the wordplay.
'good french' becomes 'bon' ('good' in French).
'name' becomes 'n' (common abbreviation e.g. on forms).
'bon'+'n'='BONN'
'for' acts as a link.
(Other definitions for bonn that I've seen before include "Former capital of the German Federal Republic" , "Capital of West Germany, 1949-1990" , "W German capital 1949-90" , "old European capital" , "West German capital, 1949-90" .)