Dingy church in French port (7)
I believe the answer is:
dunkirk
'french port' is the definition.
(I know that Dunkirk is an port)
'dingy church' is the wordplay.
'dingy' becomes 'dun' (both can mean dark or dull in colour).
'church' becomes 'kirk' (kirk is a kind of church).
'dun'+'kirk'='DUNKIRK'
'in' is the link.
(Other definitions for dunkirk that I've seen before include "Site of nineteen forty nine Allied evacuation" , "Scene of Allied troop evacuation, 1940" , "French seaport from which British troops were evacuated in 1940" , "Scene of the evacuation of British forces in 1940" , "Crisis where a desperate effort is the only alternative to defeat?" .)