1. L'As du Fallafel — Le Marais (4th)
The most famous falafel in Paris, in the middle of Rue des Rosiers.
L'As du Fallafel is the landmark of Rue des Rosiers. Its signature is a falafel sandwich served with fried eggplant and hummus, and the lunchtime line often runs into the street because the dining room is small. Wikipedia lists it as a kosher meat restaurant and says it is closed on Shabbat.
Guides disagree on weekday closing times, from about 11 pm to midnight, and agree that it closes early on Fridays and all day Saturday. There is no official website, so call before a special trip.
Good to know: Take it away and eat it on the street rather than queue for a table. Closed Saturday, and shut on Friday afternoon. Confirm the kosher certificate displayed at the shop.
34 Rue des Rosiers, 75004 Paris, France