@movieormaybe Honestly, I would take as much time as you can to see Paris. It's one of those places that you want to be able to be leisurely in, but there's still an intimidating amount to see. Considering you could spend your whole life just wandering the art museums, if that's your thing. So I'd suggest 5 days if you can get away with it.
And the Marais is my favorite neighborhood! If you go, you MUST eat a falafel sandwich at L'as du Falafel. There will be a long line, but it will change your life!