True Frenchman in province (5)
I believe the answer is:
realm
'province' is the definition.
(I've seen this before)
'true frenchman' is the wordplay.
'true' becomes 'real' (synonyms).
'frenchman' becomes 'm' (abbreviation for Monsieur - like 'Mr').
'real'+'m'='REALM'
'in' is the link.
(Other definitions for realm that I've seen before include "World" , "Lamer (anag.)" , "region" , "department" , "Kingdom, domain" .)