Hair used in Montmartre's salons (5)
I believe the answer is:
tress
'hair' is the definition.
(I know that tress is a type of coif)
'in montmartre's salons' is the wordplay.
'in' indicates a hidden word.
'TRESS' is hidden in the letters of 'montmartres salons'.
'used' acts as a link.
(Other definitions for tress that I've seen before include "Obsolete support" , "Braid of hair" , "Long piece of hair" , "Curl - lock" , "Long lock or plait of hair" .)