Very French, run following invasion! (8)
I believe the answer is:
trespass
'invasion' is the definition.
(thesaurus)
'very french run following' is the wordplay.
'very french' becomes 'tres' ('very' translated into French).
'run' becomes 'pass' ('pass' can be a synonym of 'run'**).
'following' is a charade indicator (letters next to each other).
'tres'+'pass'='TRESPASS'
(Other definitions for trespass that I've seen before include "Enter another's property unlawfully" , "Illegal entry" , "Enter another's property without permission" , "Intrude, encroach" , "Intrude on another's property" .)