Novel in biro about a city (7)
I believe the answer is:
nairobi
'city' is the definition.
(Nairobi is an example)
'novel in biro about a' is the wordplay.
'novel' indicates an anagram (letters in a new or novel order).
'about' means one lot of letters goes inside another.
'in'+'biro'='inbiro'
'inbiro' anagrammed gives 'nirobi'.
'nirobi' enclosing 'a' is 'NAIROBI'.
(Other definitions for nairobi that I've seen before include "Robinia strangely found in Kenya" , "The capital of Kenya (7)" , "Kenyan city" , "I, a robin (anag) - city" , "Foreign capital" .)