Surprise opening by the French (7)
I believe the answer is:
startle
'surprise' is the definition.
(to startle someone is to surprise or shock them)
'opening by the french' is the wordplay.
'opening' becomes 'start' (both can mean the beginning).
'by' means one lot of letters go next to another.
'the french' becomes 'le' ('the' in French).
'start'+'le'='STARTLE'
(Other definitions for startle that I've seen before include "Scare" , "Cause shock to" , "Surprise with starlet" , "Cause to jump" , "Frighten suddenly" .)