Apply extradition of French harbour (6)
I believe the answer is:
deport
'apply extradition' is the definition.
I can't tell whether this definition defines the answer.
'of french harbour' is the wordplay.
'of french' becomes 'de' ('of' in French).
'harbour' becomes 'port' (I've seen this before).
'de'+'port'='DEPORT'
Can you help me to learn more?
(Other definitions for deport that I've seen before include "Expel unwanted person from country" , "Expel from country - not a citizen" , "Exile" , "Remove an unwanted person from a country" , "Evict an alien" .)