Doing nothing about French breach (10)
I believe the answer is:
infraction
'breach' is the definition.
(I've seen this before)
'doing nothing about french' is the wordplay.
'doing nothing' becomes 'inaction' (I've seen this before).
'about' is an insertion indicator.
'french' becomes 'fr'.
'inaction' placed around 'fr' is 'INFRACTION'.
(Other definitions for infraction that I've seen before include "transgression" , "Breach of agreement" , "Violation of law" .)