A long name for a German city (6)
I believe the answer is:
aachen
'german city' is the definition.
(I've seen this before)
'a long name for a' is the wordplay.
'a long' becomes 'ache' (I've seen this before).
'name' becomes 'n' (common abbreviation e.g. on forms).
'for' is a charade indicator (letters next to each other) (I've seen this in other clues).
'ache'+'n'='achen'
'achen' put after 'a' is 'AACHEN'.
(Other definitions for aachen that I've seen before include "spa town" , "Whither good news was brought" , "German spa city" , "old capital city" , "German name for Aix-la-Chapelle" .)