That's a bit shocking about the French inheritance law. It must create awful family tensions when there are more than 2 children.
Each child is entitled to 1/n of that.
If I have 5 children, I have to give them 4/5 of the inheritance. Each one will have 1/5 of that 4/5.
And in the case of a sole child, she must receive 100% of 50% of the inheritance, at least.