The French politician depressed after Catholic suppression (9)
I believe the answer is:
clampdown
'suppression' is the definition.
(I've seen this before)
'the french politician depressed after catholic' is the wordplay.
'the french' becomes 'la' ('the' in French).
'politician' becomes 'MP' (Member of Parliament).
'depressed' becomes 'down' (synonyms).
'after' is a charade indicator (letters next to each other).
'catholic' becomes 'C' (abbreviation as in RC for Roman Catholic).
'la'+'mp'+'down'='lampdown'
'lampdown' after 'c' is 'CLAMPDOWN'.
(Other definitions for clampdown that I've seen before include "Sudden restriction on an activity" , "stopper?" , "suppression" , "Restrictive practice" , "restrictive measure" .)