Again class note German artist of French extraction (7)
I believe the answer is:
regrade
'again class' is the definition.
('grade' is an answer for 'class' so perhaps 'regrade' is OK for 'again class')
'note german artist of french extraction' is the wordplay.
'note' becomes 're' (as in do-re-mi).
'german' becomes 'g' (abbreviation).
'artist of french extraction' becomes 'rade' (I can't justify this - if you can you should give a lot more credence to this answer).
're'+'g'+'rade'='REGRADE'
Can you help me to learn more?
(Other definitions for regrade that I've seen before include "Rank again" , "Alter rating" , "Give new status" .)