Frenchman clothes a gentleman in French label again (6)
I believe the answer is:
rename
'label again' is the definition.
('name' is an answer for 'label' so perhaps 'rename' is OK for 'label again')
'frenchman clothes a gentleman in french' is the wordplay.
'frenchman' becomes 'rene' (common French name).
'clothes' means to remove the middle letters (only the letters which clothe the word remain).
'a gentleman in french' becomes 'name' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'rene' with its centre removed is 're'.
're'+'name'='RENAME'
Can you help me to learn more?
(Other definitions for rename that I've seen before include "Rechristen" , "Confer new appellation of meaner sort" , "Brand again" , "Give a new title to" , "Call again" .)