He created unusual sculptures of the French prize winner (7)
I believe the answer is:
duchamp
'he created unusual sculptures' is the definition.
(French artist Marcel Duchamp)
'of the french prize winner' is the wordplay.
'of the french' becomes 'du' ('of the' in French).
'prize winner' becomes 'champ' (short for champion).
'du'+'champ'='DUCHAMP'
(Other definitions for duchamp that I've seen before include "US painter" , "US artist" , "Marcel --, French artist" , "French-born artist" .)