Sort out French article with composer (7)
I believe the answer is:
unravel
'sort out' is the definition.
(I've seen this before)
'french article with composer' is the wordplay.
'french article' becomes 'un' (indefinite article in French).
'with' is a charade indicator (letters next to each other).
'composer' becomes 'ravel' (Maurice Ravel, 1875-1937).
'un'+'ravel'='UNRAVEL'
(Other definitions for unravel that I've seen before include "Unpick, untangle" , "Make sense of" , "Disentangle knitted wool or solve mystery" , "Undo; begin to collapse" , "Solve the problem" .)