In the 9th century, France enacted into law a way to buy and sell property through something known as une vente en viager. Here's how it typically works.

Whoever buys it will usually pay you, the seller, in two ways. They will pay you an upfront lump sum (called le bouquet) and a recurring payment (called la rente viagère) up until the day you die (or both of you die). Once this happens, the buyer then gets full enjoyment of the property. The transaction is complete.

So why would either party want to sell and buy in this way?

Full blog post here:

So why would either party want to sell and buy in this way?

Full blog post here: https://brandondonnelly.com/how-viager-transactions-work-in-france-1

You're an older person (or older couple) and you want to use your home to generate some cash, but you also want to stay living in your home until the very end. So you offer it up for sale en viager occupé.