French coin a name for their emperor (8)
I believe the answer is:
napoleon
'french coin' is the definition.
(historical French coin)
'a name for their emperor' is the wordplay.
I cannot quite see how this works, but
'a' is found in the answer.
'name' could be 'leo' and 'leo' is present in the answer.
This may be the basis of clue (or it may be nonsense).
(Other definitions for napoleon that I've seen before include "Frenchman known as The Little Corporal" , "Gold twenty franc piece" , "No one, pal, matches this Little Corporal" , "Ex-dictator" , "Open loan to the French general. strangely" .)