Hi, I spoke to my notaire last March about this as I am not married and have no children. 1/4 of your french estate goes to each parent (provided they are alive). The remainder will go to your siblings in equal shares. However, if you want to bypass this process hence in your case leaving it to your niece (only siblings part), then you need to provide your notaire with following details Name, address, date of birth, name of parents. Also if your niece is not alive by then who your estate goes to eg her husband, kids or someone else. I was given a fee of 150euros for this work. However, if I want to make alterations at a later date it will cost me a lot more. Hope this helps