The French aristocrat given a pardon (3,3)
I believe the answer is:
let off
'a pardon' is the definition.
(thesaurus)
'the french aristocrat given' is the wordplay.
'the french' becomes 'le' ('the' in French).
'aristocrat' becomes 'toff' (toff can mean an upper-class person).
'given' is a charade indicator (letters next to each other).
'le'+'toff'='LET OFF'
(Other definitions for let off that I've seen before include "given a reprieve" , "Detonate" , "Fire escape" , "Pardon - discharge" , "Fired" .)