Carefully chosen by Ray, French sweetie and revolutionary (9)
I believe the answer is:
recherche
'carefully chosen' is the definition.
Both the definition and answer are adjectives. Perhaps there's an association between them I don't understand?
'ray french sweetie and revolutionary' is the wordplay.
'ray' becomes 're' (ray is another spelling of the musical note re).
'french sweetie' becomes 'cher' (I am not sure about this - if you are sure you should believe this answer much more).
'and' says to put letters next to each other.
'revolutionary' becomes 'Che' (Che Guevara the Marxist revolutionary).
're'+'cher'+'che'='RECHERCHE'
'by' is the link.
Can you help me to learn more?
(Other definitions for recherche that I've seen before include "choice" , "Rare, exotic, obscure" , "Rare or exotic (French)" , "Little-known" , "Rare or far-fetched, like her creche" .)