Can anyone recommend some good vegetarian restaurants in Paris?
I haven't eaten there, but Le Potager du Marais on rue Rambuteau (close to Centre Pompidou) gets good reviews.
I am morally opposed to eating vegetarians
Please try this link, http://www.happycow.net/ There is also an app for this link.
phred, try some fleur de sel.
Seriously though, as a former vegetarian, I'm not the best person to answer, other than to say the best vegetarian item I had in Paris was the fallafel from L'As du Fallafel-with eggplant, with hot sauce, really good. In the Marais.
I am vegan and took my two teenage daughters to Paris last week. Knowing my kids would veto my dining choices, I didn't research vegetarian or vegan restaurants, but my sense from exploring various neighborhoods is that vegetarian restaurants are few and far between. We thought that L'as du falafel (previously mentioned) was excellent (and a gastronomic respite for me). We stayed at Hotel St. Paul le Marais because of Rick's guidebook recommendation, and found it delightful in every way.
I've eaten at Le Potager du Marais on rue Rambuteau and it is excellent.
If you've got tons of cash, famed chef Alain Ducasse turned his restaurant at Plaza Athenee into a vegetarian mecca, see http://www.france24.com/en/20140905-france-top-chef-goes-almost-vegetarian/ .
Below is a list that I sent to a friend who is vegetarian who went to Paris last year along with my notes for her on them.
L'Arpege (Michelin 3 Star with corresponding prices)
84 Rue de Varenne 75007
L'As du Falafel and most of the other falafel shops on Rue Rosier
34, rue des Rosiers (4th Arrondissement)
5 Rue des Petits Champs (2nd)
Le Grenier de Notre Dame (in the 5th somewhere -- I've never been but it is the first vegetarian restaurant in Paris)
Le Potager du Marais
24 Rue Rambuteau (excellent)
Au Grain de Folie (In Montmartre, never been but heard that is very cozy and great)
20 Rue de la Pierre Levee (over in the 11th so sort of far from touristy spots but in a hip, urban neighborhood)
Cafe Breizh (Crepes and really, really good casual place)
109 Rue Vieille du Temple
just as an aside, there are frequent posts on Japan travel forums about the impossibility of finding food that doesn't have at least a bit of beef or pork in it, even when the establishment proudly proclaims that they serve vegetarian.