French film-maker turned in a success, with restless music (7)
I believe the answer is:
agitato
'restless music' is the definition.
(music played in an agitated manner)
'french film-maker turned in a success' is the wordplay.
'french film maker' becomes 'Tati' (actor and filmmaker Jacques Tati).
'turned' says the letters should be written in reverse.
'in' indicates putting letters inside.
'success' becomes 'go' (I've seen this in other clues).
'tati' back-to-front is 'itat'.
'a'+'go'='ago'
'itat' placed within 'ago' is 'AGITATO'.
'with' is the link.
(Other definitions for agitato that I've seen before include "Musically, to be performed vigorously" , "Restless, wild (mus.)" , "Restlessly (music)" , "stirred up" , "frenetically scored" .)