Time in French capital gains a new supporter (8)
I believe the answer is:
partisan
'supporter' is the definition.
(I know that partisan is a type of supporter)
'time in french capital gains a new' is the wordplay.
'time' becomes 't' (abbreviation).
'in' is an insertion indicator.
'french capital' becomes 'Paris' (capital of France).
'gains' is a charade indicator (letters next to each other).
'new' becomes 'n' (common abbreviation eg NT for New Testament).
't' inserted within 'paris' is 'partis'.
'partis'+'a'+'n'='PARTISAN'
(Other definitions for partisan that I've seen before include "In Sparta (anag)" , "Prejudiced in favour of a particular cause" , "Prejudiced towards a particular cause" , "of prejudiced views" , "Unquestioning supporter -- aspirant (anag)" .)