An aperitif of French; it’s for the head (8)
I believe the answer is:
dubonnet
'an aperitif' is the definition.
(I've seen this before)
'of french it's for the head' is the wordplay.
I cannot quite understand how this works, but
'of' could be 'o' and 'o' is present in the answer.
'the' could be 't' (the is pronounced as a 't' sound in some dialects) and 't' is found within the answer.
'it' could be 'e' ('e' can mean 'electronic' which is similar to 'IT') and 'e' is located in the answer.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Another definition for dubonnet that I've seen is " Tub on end (anag) - aperitif".)