French art shown in dull Italian port (7)
I believe the answer is:
trieste
'italian port' is the definition.
(I've seen this before)
'french art shown in dull' is the wordplay.
'french art' becomes 'es' ('is' in French - 'art' can mean 'is' eg 'thou art').
'shown in' indicates putting letters inside.
'dull' becomes 'trite' (I've seen this before).
'es' placed within 'trite' is 'TRIESTE'.
(Other definitions for trieste that I've seen before include "Italian seaport" , "Italian city, James Joyce's 13" , "One would have found a testier James Joyce there" , "NE Italy port" , "Italy port, near Slovenia" .)