Appeal to doctor in French first (7)
I believe the answer is:
entreat
'appeal to' is the definition.
(thesaurus)
'doctor in french first' is the wordplay.
'doctor' becomes 'treat' (I've seen this before).
'in french' becomes 'en' ('en' can be French for 'in' e.g. en France).
'first' is a charade indicator (letters next to each other).
'treat' after 'en' is 'ENTREAT'.
(Other definitions for entreat that I've seen before include "Beg earnestly, appeal" , "Ask (someone) earnestly" , "Pray" , "Will's pass" , "Beg earnestly, beseech" .)