Delight in French song (7)
I believe the answer is:
enchant
'delight' is the definition.
(enchant can mean to charm or delight)
'in french song' is the wordplay.
'in french' becomes 'en' ('in' in French).
'song' becomes 'chant' (song sung by a crowd).
'en'+'chant'='ENCHANT'
(Other definitions for enchant that I've seen before include "Beguile" , "Fascinate - delight" , "Appeal" , "Delight or bewitch" , "Delight, charm" .)