I must admit, I did not search for vegan or vegetarian specific places in Paris. My mother had her places and there we went. Trying to veganize things in France is difficult, needless to say. Unless you know French or you have English-speaking wait staff... good luck.
I hear good things about this place: La Victoire Suprême du Coeur. It is the picture in this blog post.
Perhaps another time I will explore vegan Paris, c'est la vie!
And for good measure: the loveliest place on Earth... The Eiffel Tower at night!