Set about penning short study on French values (9)
I believe the answer is:
treasures
'values' is the definition.
('treasure' can be a synonym of 'value')
'set about penning short study on french' is the wordplay.
'about' says the letters should be written in reverse.
'penning' indicates putting letters inside.
'short study on' becomes 'rea' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'french' becomes 'sur' (I've seen this in other clues).
'set' reversed gives 'tes'.
'rea'+'sur'='reasur'
'tes' enclosing 'reasur' is 'TREASURES'.
Can you help me to learn more?
(Other definitions for treasures that I've seen before include "Holds dear, prizes" , "lots of valuables" , "Values" .)