Follow in French girl (5)
I believe the answer is:
ensue
'follow' is the definition.
(ensue can mean to follow or happen as a result)
'in french girl' is the wordplay.
'in french' becomes 'en' ('in' in French).
'girl' becomes 'sue' (girl's name).
'en'+'sue'='ENSUE'
(Other definitions for ensue that I've seen before include "Arise" , "Happen or come about as consequence" , "Come about, result in" , "Cultivate plants/vegetables" , "Come along afterwards" .)