One Frenchman said to have grabbed another? That’s not right (7)
I believe the answer is:
immoral
'not right' is the definition.
(I've seen this in another clue)
'one frenchman said' is the wordplay.
'one' becomes 'im' (I can't justify this - if you can you should give a lot more credence to this answer).
'frenchman' becomes 'm' (abbreviation for Monsieur - like 'Mr').
'said' becomes 'oral' (I've seen this before).
'im'+'m'+'oral'='IMMORAL'
'to have grabbed another? that's' is the link.
This may not be correct. Some or all of it may be part of another bit of the clue.
Can you help me to learn more?
(Other definitions for immoral that I've seen before include "Lacking a sense of right and wrong" , "Sexually dissolute" , "Wicked" , "Without values" , "dishonest" .)