If you have a french bank account this should be a priority.
The notaire should provide a document called certificate ( or attestation) of sale which may be requested by utilities etc. when you cancel the contract. I can't remember now how I cancelled, but probably registered letter is best.
Our immo sent us these certificates by email.
We only just sorted payment of the TdH, or may TF a few weeks ago , plod. The man in charge of local taxes where we lived was very helpful, I contacted him by email.
To the OP- don't you have house insurance, or other insurances?