Release upper-class type supporting the French (3,3)
I believe the answer is:
let off
'release' is the definition.
(thesaurus)
'upper-class type supporting the french' is the wordplay.
'upper-class type' becomes 'toff'.
'supporting' says to put letters next to each other (in a down clue, some letters go below others).
'the french' becomes 'le'.
'toff' put after 'le' is 'LET OFF'.
(Other definitions for let off that I've seen before include "not guillotined?" , "Chance to escape defeat" , "Spare" , "Fired" , "Discharge - absolve" .)