Partly unseals a cellar in French wine region (6)
I believe the answer is:
alsace
'french wine region' is the definition.
(I've seen this in another clue)
'partly unseals a cellar' is the wordplay.
'partly' says the answer is hidden in the clue (part of the clue is used).
'ALSACE' is hidden in the letters of 'unseals a cellar'.
'in' acts as a link.
(Other definitions for alsace that I've seen before include "Filled pastry" , "French region bordering Germany and Switzerland" , "White wine region of northeast France" , "source of French wines" , "Region of France famous for white wine" .)