How do you say are the light of my life in French?

There isn't a perfect direct translation of "You are the light of my life" in French that captures the same sentiment. However, here are a few options:

Formal:

* Vous êtes la lumière de ma vie. (This is the most literal translation but can sound a bit stiff.)

* Vous illuminez ma vie. (This means "You illuminate my life" and conveys the idea of joy and brightness.)

Informal:

* Tu es le soleil de ma vie. (This means "You are the sun of my life" and is a more romantic way to say it.)

* Tu es tout pour moi. (This means "You are everything to me" and is a very loving and affectionate way to say it.)

The best way to express this sentiment in French would depend on the context and your relationship with the person you're talking to.