 Mathias quickly learns that the apartment is a "viager" — an ancient French system for buying and selling apartments — and that he will not actually be in possession of the apartment until Mathilde dies, and that until then he owes her a life annuity of €2,400 a month.All this is a surprise to him, since his father never told him and Mathias had language problems with the French lawyer.Mathias has no money and no place to live, but Mathilde allows him to stay in the apartment with her if he pays rent.