Formal:
* À bientôt: This is the most common and versatile way to say "see you soon."
* À très bientôt: This means "see you very soon" and is more enthusiastic.
Informal:
* On se voit bientôt: This literally translates to "we see each other soon" and is a more friendly way to say it.
* À plus tard: This means "see you later" and is appropriate for friends or family.
* Ciao: This is an informal greeting and farewell, borrowed from Italian, that can also mean "see you soon."
You can also use a more specific phrase depending on the context:
* Je te retrouve plus tard: "I'll see you later" (more casual)
* On se retrouve demain: "See you tomorrow"
* Je te vois la semaine prochaine: "See you next week"
Remember to choose the phrase that best fits the situation and your relationship with the person you are speaking to.