How to transfer shares in SCI?

[JT]

My mother, sister and I bought a property in France some time ago and set up an SCI for the purpose.  My Mother has been thinking about giving us her share to avoid any future inheritance tax liabilities.  I understand we could do this by making a gift transfer of her share to someone else but have no idea how we would go about it.

Do we need a notaire in France?  What taxes or costs would we have to pay?  Can we transfer it to someone not already in the SCI?

Thanks for any help

JT  [8-)]