French	English	When
Bonjour	Hello / Good day	All day — never skip it
Bonsoir	Good evening	Mainly when arriving in the evening
Salut	Hi / Bye	Friends only
Au revoir	Goodbye	The standard farewell, with anyone
À bientôt	See you soon	When you expect to meet again
Bonne soirée	Have a nice evening	Leaving in the evening
Bonne nuit	Good night	Only at bedtime
Comment allez-vous ?	How are you?	Polite, with vous
Très bien, merci.	Very well, thank you.	The standard reply

Bonsoir is mainly for arriving; bonne soirée is for leaving. Bonne nuit is not an evening greeting: it's what you say when someone is going to bed.