When there is nothing to be done during your lunch time, I have a recommendation. Fill your eat hole with poutine. The kind of dish your taste buds will thank you for, but perhaps the incoming future heart issues might make you regret.
So far the best poutine I’ve had in Paris has been in The Moose (side note the chicken wings are divine) and not exactly expensive either (by Paris 6ème standards). But it’s hard to write words about stuffing great food down my face, so just look at dem pix fam.