La Mère Lachaise is, as the name suggests, near the Père Lachaise cemetery in the 20th arrondissement. It is informal and provides good, fresh, contemporary French food at a modest price. My commentary on a recent visit is here.
Wow, if the formula dejeuner carte applies for all entrees and plats shown, that is indeed very attractive pricing for what sounds like pretty good quality from your review.
No, alas. If you look closely, it only applies to those items marked with two red stars.
I believe I was at this location in 2000, when a friend roped about 20 of us into visiting Paris for her 50th birthday. It was old-school French cuisine in those days, with an upstairs dining room.
Wow, that looks amazing, I am thinking Lunch and then a visit to the cemetery to walk it off!