It's very French to overtake in error (8)
I believe the answer is:
trespass
'error' is the definition.
(thesaurus)
'it's very french to overtake' is the wordplay.
'it's very french' becomes 'tres' ('very' translated into French).
'to overtake' becomes 'pass' ('pass' can be a synonym of 'overtake').
'tres'+'pass'='TRESPASS'
'in' is the link.
(Other definitions for trespass that I've seen before include "Invade" , "Enter another's property unlawfully" , "offence" , "Enter another's property without permission" , "Enter land illegally" .)