Formal:
* Adieu: This is the most formal and literary way to say farewell, often used in written texts or when addressing someone with high social standing.
* Au revoir: This is the most common and versatile way to say goodbye, suitable for almost all situations.
* Je vous souhaite une bonne journée/soirée: This literally translates to "I wish you a good day/evening" and is a polite way to say goodbye.
Informal:
* Salut: This is a casual way to say goodbye, similar to "bye" in English.
* Ciao: This is a more informal and modern way to say goodbye, often used among younger people.
* Bonne journée/soirée: This is a less formal way to say "have a good day/evening".
Other expressions:
* Bonne chance: This means "good luck" and is often used as a farewell, especially when someone is embarking on a new venture.
* À bientôt: This means "see you soon" and is a warm way to say goodbye.
The best way to say farewell in French depends on your relationship with the person you are saying goodbye to and the situation.