Debt-collector at church in France (7)
I believe the answer is:
dunkirk
'in france' is the definition.
('Dunkirk' is part of 'france')
'debt-collector at church' is the wordplay.
'debt collector' becomes 'dun' (historical term for a debt collector).
'at' says to put letters next to each other.
'church' becomes 'kirk' (kirk is a Scottish term for a church).
'dun'+'kirk'='DUNKIRK'
(Other definitions for dunkirk that I've seen before include "Channel port" , "Crisis where a desperate effort is the only alternative to defeat?" , "French port, scene of a 1940 Allied evacuation" , "Scene of Allied troop evacuation, 1940" , "Scene of the evacuation of British forces in 1940" .)