European cop the French sanction (6)
I believe the answer is:
enable
'sanction' is the definition.
(thesaurus)
'european cop the french' is the wordplay.
'european' becomes 'e' (abbreviation e.g. EU).
'cop' becomes 'nab' ('nab' can be a synonym of 'cop').
'the french' becomes 'le'.
'e'+'nab'+'le'='ENABLE'
(Other definitions for enable that I've seen before include "Authorise" , "Capacitate" , "Empower" , "Render capable" , "Give power or capacity to" .)