One opens doors for Montmartre pawnbroker (5)
I believe the answer is:
uncle
'pawnbroker' is the definition.
(old-fashioned term for a pawnbroker)
'one opens doors for montmartre' is the wordplay.
I cannot really understand how this works, but
'one' could be 'un' (I've seen this in other clues) and 'un' is located in the answer.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for uncle that I've seen before include "older relative" , "Sam, perhaps" , "Law enforcement body" , "Male family member" , "Dad's brother" .)