A little French competition at heart (5)
I believe the answer is:
petit
'a little' is the definition.
(thesaurus)
'french competition at heart' is the wordplay.
'at heart' indicates the answer is hidden within the clue (letters hidden in the heart of the clue).
'PETIT' is hidden in the letters of 'french competition'.
(Other definitions for petit that I've seen before include "Small to the French" , "Minor in court" , "- Four is a fancy biscuit" , "Not great" , "Insignificant amount" .)