British School of Language in Rennes (6)
I believe the answer is:
breton
'language in rennes' is the definition.
'Breton' can be an answer for 'language' (Breton is an example). I am not sure about the 'in rennes' bit.
'british school' is the wordplay.
'british' becomes 'br' (abbreviation for British).
'school' becomes 'eton' (famous UK public school).
'br'+'eton'='BRETON'
'of' acts as a link.
Can you help me to learn more?
(Other definitions for breton that I've seen before include "Inhabitant of northwest France" , "Inhabitant of NW France" , "Frenchman" , "Person from Brittany" , "Language of NW France" .)