Belgian city, for example, in piece of fiction (5)
I believe the answer is:
liege
'belgian city' is the definition.
(I've seen this before)
'example in piece of fiction' is the wordplay.
'example' becomes 'eg'.
'in' is an insertion indicator.
'piece of fiction' becomes 'lie' (I've seen this before).
'eg' put within 'lie' is 'LIEGE'.
'for' is the link.
(Other definitions for liege that I've seen before include "European city" , "Bound to render feudal service" , "Feudal (lord); vassal" , "Large Belgian city" , "Loyal vassal" .)