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' says to put letters next to each other.
'composer' becomes 'ravel' (Maurice Ravel).
'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" .)