The man Bill’s behind French footballer's famous attacking move (8)
I believe the answer is:
headbutt
'french footballer's famous attacking move' is the definition.
I can't judge whether this definition defines the answer.
'the man bill's behind' is the wordplay.
'the man' becomes 'he' (pronoun for a man).
'bill' becomes 'ad' (advertisement stuck on wall).
'behind' becomes 'butt' (both can mean the buttocks).
'he'+'ad'+'butt'='HEADBUTT'
Can you help me to learn more?
(Other definitions for headbutt that I've seen before include "nut" , "personal assault" .)