One French assistant died alone (7)
I believe the answer is:
unaided
'alone' is the definition.
(I've seen this in another clue)
'one french assistant died' is the wordplay.
'one french' becomes 'un' ('one' in French).
'assistant' becomes 'aide' (aide is a kind of assistant).
'died' becomes 'd' (abbreviation next to the year of someone's death).
'un'+'aide'+'d'='UNAIDED'
(Other definitions for unaided that I've seen before include "Done by oneself alone" , "Without extra help" , "Without help or support" , "Dun aide being without help" , "having received zero help" .)