However, there are many other equally beautiful parks around Paris such as the Parc Butte Chaumont as well as Parc de la Villette in the 19th arrondissement.
My favorite, however, is the Parc Montsouris located in the 14th arrondissement by Cite Universitaire. I would've never known about this magnificent place if I hadn't lived right by it. Check out the scene from the 14th district in the movie "Paris, je t'aime" just to get a feel!
The park offers a non-toursity scene.
There are always locals taking a few laps around the parks while walking their dogs and chatting up a few lines with each other.
I go to the park several times a week in the morning to jog. Along my jog, there is always the man walking his hairy and messy dog, carrying the same plastic bag from a local used bookstore. Then there is an upbeat lady around 60 years old that does her half walk half jog everyday. There's also a short older Asian jogger who is always happy and upbeat. Every now and then a group of fireman will arrive in their firetruck and do a few laps around the park, a site that I particularly don't mind given they do wear their short shorts!
There's a beautiful lake on the bottom corner with black and white swans, ducks, and all sorts of avian creatures. In the winter when the temperatures are low enough, the lake freezes over into a postcard like scenery. In the spring time you get to see the baby ducks following their mother around.
On weekends parents bring along their young ones to the park where they can enjoy rides, have a crepe, ride ponies, or go to a puppet show at a small theatre inside the park.
The jardin du Luxembourg prohibits visitors to sit on any of the grassy areas; and this rule is heavily enforced by annoying park guards blowing their whisles at you. At Montsouris however, people are allowed to freely sit and picnic on many of the grassy hills it has to offer. On a beautiful sunny evening, it is the perfect place to picnic, to sit and chat, have a drink, or simply just to read.
Oh and another perk, the park has... yes! Free toilets, while others will charge you up to 50 cents!