Said by the Frenchman to be the same (5)
I believe the answer is:
ditto
'be the same' is the definition.
(ditto means the same as previously mentioned)
I cannot understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for ditto that I've seen before include "As given above" , "Repeat the word(s) above" , "Duplicate" , "couple of marks" , "that which has been said" .)