Deposit for French house purchase

I am about to sign a Compromis de Vente and have been asked for a deposit of 10% of the purchase price.

I am dealing directly with a notaire. I know this figure is often quoted in articles but was wondering if it is in any way negotiable.

Thanks for your help.

A deposit is usually lodged but it's not obligatory. It is usually 10% but it can be 5% or whatever both parties agree to.