Annoy the Parisian after final (6)
I believe the answer is:
nettle
'annoy' is the definition.
(I know that annoy can be written as nettle)
'the parisian after final' is the wordplay.
'the parisian' becomes 'le' (definite article in French).
'after' means one lot of letters go next to another.
'final' becomes 'nett' (I've seen this before).
'le' put after 'nett' is 'NETTLE'.
(Other definitions for nettle that I've seen before include "Wild plant - annoy" , "To be annoying" , "Stinging plant; annoy" , "sample of herbal tea?" , "Irritate, annoy" .)