Clear a Parisian complex (13)
I believe the answer is:
uncomplicated
'clear' is the definition.
(thesaurus)
'a parisian complex' is the wordplay.
'a parisian' becomes 'un'.
'complex' becomes 'complicated' ('complicated' can be similar in meaning to 'complex').
'un'+'complicated'='UNCOMPLICATED'
(Other definitions for uncomplicated that I've seen before include "Simple" , "Straightforward" .)