Vale in Provence long swathed in gold (5)
I believe the answer is:
adieu
'vale in provence' is the definition.
(French 'goodbye' - 'vale' once meant goodbye)
'long swathed in gold' is the wordplay.
'long' becomes 'die' (to long for or to die for something is to crave it).
'swathed in' is an insertion indicator (swathe can mean to wrap).
'gold' becomes 'au' (Au is the chemical symbol for gold).
'die' going into 'au' is 'ADIEU'.
(Other definitions for adieu that I've seen before include "Goodbye in France" , "farewell message" , "I'm away (in France?)" , "Au revoir (to a kind friend?)" , "12 Down" .)