A game to the French to be played soundly (7)
I believe the answer is:
whistle
'be played soundly' is the definition.
I can't judge whether this defines the answer.
'a game to the french' is the wordplay.
'a game' becomes 'whist' (whist is a card game).
'to the french' becomes 'le' ('the' in French).
'whist'+'le'='WHISTLE'
'to' is the link.
Can you help me to learn more?
(Other definitions for whistle that I've seen before include "Make cheerful sound" , "Call vainly for" , "something needing wetting?" , "L.S.White (anag.)" , "Become an informer" .)