There is so much great vegan and vegetarian food in Paris nowadays! It seems to be becoming more popular.
I had the opportunity to visit one of my all time favorite places a few weeks ago: http://vege-saveurs.com/
For starters, I would recommend this book: http://www.gibertjoseph.com/paris-vegetarien-6066523.html (about 5 euros at Gibert Josph)
A few things have changed since 2015; for example, here is a new one near Rue des Martyres http://lapalanchedaulac.fr/ and also, what was formerly Pousse Pousse is now “5 Lorette,” in more or less the same location.
There is even a vegan brasserie, in front of which I saw people smoking. It is France, after all. https://vegoresto.fr/paris/brasserie-lola/
I didn’t go to the one in Paris, but the one in Amsterdam was superb: http://www.maozusa.com/restaurants/locations/paris
Imagine: a middle-eastern restaurant without the frickin’ side of lamb cooking!!