Severe test of French in examination (6)
I believe the answer is:
ordeal
'severe test' is the definition.
(I've seen this before)
'of french in examination' is the wordplay.
'of french' becomes 'de'.
'in' indicates putting letters inside.
'examination' becomes 'oral' (oral is a kind of examination).
'de' placed into 'oral' is 'ORDEAL'.
(Other definitions for ordeal that I've seen before include "Long painful experience" , "Disturbing experience" , "Torment" , "A difficult or harrowing time" , "Difficult experience, a tough time" .)