He's telling tales to monsieur (9)
I believe the answer is:
raconteur
'he's telling tales to monsieur' is the definition.
The answer is a person as well as being a singular noun. This is suggested by the definition.
'he's' is the wordplay.
I cannot quite understand how this works, but
'he' could be 'con' and 'con' is found within the answer.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for raconteur that I've seen before include "Amusing fellow" , "source of stories?" , "A good teller of tales" , "Skilful teller of tales" , "one with a gift for relation" .)