The French aristocrat spared the guillotine, perhaps (3,3)
I believe the answer is:
let off
'spared the guillotine perhaps' is the definition.
I can't judge whether this defines the answer.
'the french aristocrat' is the wordplay.
'the french' becomes 'le' ('the' in French).
'aristocrat' becomes 'toff' (toff can mean an upper-class person).
'le'+'toff'='LET OFF'
Can you help me to learn more?
(Other definitions for let off that I've seen before include "Not punished at all" , "Spare" , "Don't impose penalty or allow to dismount" , "Released - shot - treated leniently" , "not guillotined?" .)