In this big house in France the cat has water (7)
I believe the answer is:
chateau
'in this big house in france' is the definition.
The definition suggests a singular noun which matches the answer.
'cat has water' is the wordplay.
'cat has' becomes 'chat' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'water' becomes 'eau' (I have seen 'French water ' mean 'eau' so perhaps 'water' could also mean 'eau').
'chat'+'eau'='CHATEAU'
'the' acts as a link.
Can you help me to learn more?
(Other definitions for chateau that I've seen before include "French country home" , "Large French country house" , "French castle or manor" , "country house in Bordeaux?" , "Loire Valley attraction" .)