Possessions in French art gallery (6)
I believe the answer is:
estate
'possessions' is the definition.
(I've seen this before)
'french art gallery' is the wordplay.
'french art' becomes 'es' ('is' in French - 'art' can mean 'is' eg 'thou art').
'gallery' becomes 'tate' (I've seen this before).
'es'+'tate'='ESTATE'
'in' acts as a link.
(Other definitions for estate that I've seen before include "Property left at death" , "Amount of land - type of car" , "Total possessions" , "Person's belongings after death" , "Piece of land with a lot of houses" .)