Who comes to Paris for falafel? Well, you should, because it's better than any I've had in the US. There's one place that's the most famous: L'As du Fallafel. Google "best falafel in Paris" and you'll find oodles of pictures and recommendations. So I've made this my Thursday afternoon tradition.
But then again, there's always the #1 competitor directly across the street, Mi-va-mi. They seem to have a friendly rivalry. Though both claim to have the best falafel in Paris, Mi-va-mi's line is never nearly as long as L'As du Fallafel's, which can be a blessing if we're short on time. The only real difference between the two places is the addition of an extra salsa on Mi-va-mi's part. It's mild but welcome in my case, though many people may get bogged down with so many tastes crammed into one pita.