Refer to French metropolis (4)
I believe the answer is:
cite
This clue is a double definition.
'refer' is the first definition.
(I know that refer can be written as cite)
'to french metropolis' is the second definition.
('city' in French)
(Other definitions for cite that I've seen before include "Use quotations" , "name" , "Summons - quote" , "Adduce as proof" , "Quote as evidence" .)