Head piece worn by the French peer (8)
I believe the answer is:
nobleman
'peer' is the definition.
(I've seen this in another clue)
'head piece worn by the french' is the wordplay.
'head' becomes 'nob' (slang term for the head).
'piece' becomes 'man' (man can mean a chess piece).
'worn by' indicates putting letters inside (outside letters are worn by those on the inside).
'the french' becomes 'le' ('the' in French).
'nob'+'man'='nobman'
'nobman' going around 'le' is 'NOBLEMAN'.
(Other definitions for nobleman that I've seen before include "Male aristocrat" , "Earl, say" , "count, perhaps" , "Member of the aristocracy" , "Titled person" .)