How do you say see then in French?

The closest translation of "see then" in French depends on the context:

If you mean "see you then," it would be:

* À tout à l'heure (informal)

* À plus tard (informal)

* À bientôt (more formal)

If you mean "see, then," as in "see, then it makes sense," it would be:

* Vois, alors (more colloquial)

* Tu vois, alors (more common)

It's important to consider the context and the desired tone when choosing the right translation.