Propriétaire vs. bailleur
While both words are often translated as "landlord" in English, propriétaire refers to the legal owner of the property, whereas bailleur is a technical term regarding the rental contract.
Propriétaire
A2This word literally means "owner." It is the most common term used in everyday conversation to refer to a landlord or landlady. It emphasizes that the person possesses the legal title to the real estate. You would use this word when chatting with friends or calling someone to fix a leak.
Mon propriétaire m'a donné la permission de peindre les murs.
(My landlord gave me permission to paint the walls.)
C'est difficile de devenir propriétaire à Paris à cause des prix.
(It is difficult to become an owner in Paris because of the prices.)
Le propriétaire a décidé de vendre l'appartement l'année prochaine.
(The landlord decided to sell the apartment next year.)
Si tu as une fuite d'eau, tu dois appeler ton propriétaire.
(If you have a water leak, you must call your landlord.)
Bailleur
B2This is a formal legal term equivalent to "lessor." It shares the same root as the word bail (lease). It refers to the person or entity providing the property to a tenant under a contract. While the bailleur is almost always the owner, this specific word is strictly reserved for administrative documents, contracts, and legal contexts.
Le bailleur est tenu de délivrer un logement décent.
(The lessor is required to provide decent housing.)
Veuillez envoyer votre préavis au bailleur par courrier recommandé.
(Please send your notice to the lessor by registered mail.)
Le nom et l'adresse du bailleur sont indiqués sur le contrat de location.
(The name and address of the lessor are indicated on the rental agreement.)
Le locataire et le bailleur ont signé l'état des lieux.
(The tenant and the lessor signed the inventory of fixtures.)
Summary
Use propriétaire for all casual and spoken interactions when referring to the person who owns the place. Use bailleur only when reading contracts, dealing with the law, or discussing formal obligations between the tenant and the person renting out the property.