I am in joint possession with my sister on a house. We signed a sales agreement with a buyer. My sister wants me to collect the full price. Is she still required to come and sign the deed of sale?

Yes. The notary responsible for drawing up the deed of sale must obtain the consent to the sale of all the joint owners.

As regards the breakdown of the sale price by the notary, it is made in proportion to your respective joint rights.

Note: if your sister decides to leave you the full sale price, the tax authorities may consider it a donation.