Monsieur's money (5)
I believe the answer is:
franc
'monsieur's money' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for franc that I've seen before include "It's equal to 100 centimes" , "Swiss capital" , "Former French coin" , "Historic currency" , "Nonsense (colloq.)" .)