Non-tourist places to visit in Paris?

Travel Info
What are the best places to visit in Paris that aren't super touristy? I know about the Eiffel Tower, ect. but I want something that not many people know about, and still be fun to see for a family.

Travel Tips

Part of the reason that places are "touristy" is that there is something there that is worth seeing. In a place like Paris which has millions of tourists pass thru every year its hard to name a place that isn't "touristy" to at least some extent.

Some of the less touristed places might be:

1. Mus茅e des Plans-Relief

An overlooked museum that is housed over the Army Museum on the Esplanade des Invalides. For years this place was just a garret filled with models of the various fortifications and walled towns in France. Prior to 1950 the public was not admited since some of information that could gleaned from the models was considered a state secret. The collection of models was started by Louis XIV. The oldest model, representing the town of Perpignan, dates back to 1866.

2) Arena Lutetia on the rue Monge.

These are the remains of a Roman arena destroyed in the 3rd century. Completely forgotten during 1500 years they were rediscovered in 1869, when new streets were planned and diggings ordered. It was one of the largest amphitheatres of Gaul and could accomdate at least 15,000 spectators.

3) La Maison du Haut-Pignon at 51, rue de Montmorency, Paris 3rd arr.

This is the oldest house in Paris. It was built in 1407 by the writer and alchemist Nicolas Flamel. Look at the fa莽ade and see the inscription: "Ora et labora" (pray and work), which was the motto of the alchemists.

4) Cimetiere de Picpus

This is the burial place of the Marquis de Lafayette which can be found at 35, rue de Picpus. The only way into the cemetary is through an unmarked door in a larger, perpetually-closed gateway. You have to ring the doorbell and turn to the right after you pass through the door and find the entry 'official' who takes your entry fee.

An American flag flies over his grave and did so even during the Nazi occupation of Paris.

Since you mention family, I assume you may have your kids with you. If you do this is a perfect place to teach them about this great man and the role France played in helping America gain its independance.

For myself, I visit his grave each time I am in Paris to lay a rose upon it and whisper "Lafayette...we are here"

Others
palais royale :) its a quaint little garden type deal with fountains/flowers and buildings. nice place for like a picnic. it is around the louvre... it isnt busy, not too many tourist really know about it.
been tehre done that
Apart from the previous answer; some suggestions: 1) the monument in honor of the victims of the Holocaust, at the point of the Isle de la Cit茅 (Jardin du Vert Galant) 2) The catacombs (Yes there are catacombs in Paris after all it used to be a Roman City : Lutetia), 3) the Pere Lachaise cemetery 4) The Buffet de la Gare de Lyon: This is an extremely beautiful and glamorous restaurant in the Lyon railroad station. It has paintings on the walls and ceiling from all the sites where the trains used to stop, before they became a TGV. Strangely enough it is not known to many tourists 5) The mus茅e Picasso
I vote for the Catacombs and P猫re Lachaise! My kids (10 & 6) love going there. You could also go visit the Chateau de Vincennes (end of line 1 on the metro) and then walk around the Botanical Gardens.