Serving of chicken accepted in French port (6)
I believe the answer is:
breast
'serving of chicken' is the definition.
'accepted in french port' is the wordplay.
'accepted' becomes 'a' (financial abbreviation).
'in' indicates putting letters inside.
'french port' becomes 'brest' (port city in Brittany).
'a' put within 'brest' is 'BREAST'.
(Other definitions for breast that I've seen before include "Reach the top of (a hill)" , "Mamma" , "Bit of turkey, perhaps" , "Cut of chicken" , "Cut of meat carved from a fowl" .)