Fake art's sculpted by European unknown (6)
I believe the answer is:
ersatz
'fake' is the definition.
(ersatz means fake or imitation)
'art's sculpted by european unknown' is the wordplay.
'sculpted' indicates anagramming the letters.
'by' means one lot of letters go next to another.
'european' becomes 'E' (abbreviation e.g. EU).
'unknown' becomes 'z' (algebra).
'arts' is an anagram of 'rsat'.
'rsat' put after 'e' is 'ersat'.
'ersat'+'z'='ERSATZ'
(Other definitions for ersatz that I've seen before include "Bogus" , "Imitation (from Ger.)" , "Made in imitation - in Germany" , "Artificial or inferior imitation" , "being of inferior quality" .)