He'll sell you a ticket - all in French! (4)
I believe the answer is:
tout
'all in french' is the definition.
('all' in French)
'he'll sell you a ticket' is the wordplay.
I cannot really see how this works, but
'you' could be 'u' (commonly used in online communication) and 'u' is found in the answer.
The remaining letters 'tot' is a valid word which might be clued in a way I don't see.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for tout that I've seen before include "Hawk brazenly" , "Illegal ticket seller" , "Solicit custom brazenly" , "Solicit, canvass" , "Sell (tickets) illegally" .)