... Marceau, French mime artist (6)
I believe the answer is:
marcel
I believe this clue is a double definition.
'marceau' is the first definition.
(I've seen this in another clue)
'french mime artist' is the second definition.
(I know that Marcel is a mime artist)
(Other definitions for marcel that I've seen before include "French novelist, 1871-1922" , "sort of wave" , "Frenchman" .)