Niche or unknown things to do in Paris

One of my favorite things that I did in Paris was to take a Sunday morning electric bike tour with Paris Charms and Secrets. Unlike other bike tours, you lock your bike and the guide will take you into churches, parks and other sites not normally visited by tour groups and only ridden past by other tours. And peddling the electric bikes was a great experience. I enjoyed it so much, I bought one and use it regularly.

Wonderful tip! Thank you.

I’m a gamer so I like to hit the shops with miniature figured used in role playing games like dungeons and dragons. I found a great one near the natural history museum, which has some cool dinosaur fossils.

Visit the tomb of Lafayette in the picturesque cemetery at Picpus. Note it is open very limited hours so check on the web to make sure when it is open and know exactly where it is as it doesn't exactly jump out at you.
https://janettravels.wordpress.com/2016/01/24/lafayette-we-are-here/
There is the human zoo ruins on the far side of Parc Vincennes where colonial people where exhibited during the early 1900s at the colonial exposition. The Fondation Louis Vuiton is not exactly unknown but it relatively remote in Bois du Boulogne and you can directly enter the Jardin Acclimatation an antique amusement park for children which is quite lovely from the museum.
https://janettravels.wordpress.com/2019/09/18/delights-of-jardin-acclimatation-and-fondation-louis-vuitton/

Or just walk around; here was a stroll to little known churches:
https://janettravels.wordpress.com/2013/12/17/interesting-paris-churches-off-the-beaten-track/
And one to check out what was at the end of Line 3 of the metro:
https://janettravels.wordpress.com/2010/06/20/end-of-the-line-3-levallois-to-gallieni/
And here's one on the east side of Paris which uncovered the amazing old wood painted church.
https://janettravels.wordpress.com/2011/11/06/a-wander-in-the-20th-and-19th-from-parc-belleville-to-butte-chamount/

Not necessarily "niche," but I enjoyed the Marmotten museum in the 16th arr. way more than the bigger, totally mobbed museums like the Louvre and the Musée d'Orsay. Also, the covered passages are a wonderful way to spend an afternoon—particularly so if your otherwise outdoor plans get weathered out. Those, Picpus cemetery and the Bois de Vincennes are on my list for my upcoming trip this May.

Hmmm, well, this is new but not unknown. I enjoyed the Liberation Museum during my visit last Fall. Not everything is in English but even with my pitiful French skills I learned a lot. It's free and the entrance is right across from the entrance to the Catacombs.

http://www.museeliberation-leclerc-moulin.paris.fr/en

I did not go down into the underground Command Post (claustrophobic) which is free but you have to sign up at the desk as they limit visitors down into the tunnels.

I structured my own walking route a couple of years ago looking for things related to Sainte-Genevieve - starting at Saint-Etienne-du-Mont (Midnight in Paris steps!) where her supposed relics are and walking downhill to the Pont de la Tournelle and the statue of her by the sculptor who did the Christ the Redeemer in Rio (Paul Landowski) and on to another church with her statue. Landowski has a number of sculptures in the area as well. Here is a link to another one near Trocadero on a Corey Frye (A French Frye in Paris) walking video. He talks about him at about 18:09.

https://www.youtube.com/watch?v=WMp7BtwjajA

Some of my own walks have been based on things I saw in Corey Frye's videos so do look at his youtube channel. That Trocadero one linked above had some very interesting sights on it.

Sometimes I'll stitch a route together between major sights, sometimes I'll build one that looks like it will take a couple of hours.

I also use Atlas Obscura for off beat sights. I spent time a couple of years ago looking for the statue of the Lion eating a foot at the entrance to the Jardin des Plantes ( https://www.atlasobscura.com/places/lion-of-the-botanical-gardens ) as well as the cannonball embedded in the wall at the Hotel de Sens. (https://www.atlasobscura.com/places/cannonball-of-the-hotel-de-sens )

Interested in Art Nouveau? There are several Jules Lavirotte facades in the 7th on Avenue Rapp, Rue du Grenelle and Rue du Champ de Mars area.

https://en.wikipedia.org/wiki/Jules_Lavirotte

Montparnasse Cemetery is interesting - not as big as Pere Lachaise. There are maps at the entrance. I was there in the Fall just after Jacques Chirac's death and he is buried there - so saw all the floral tributes and observed people coming by to pay their respects.

Hit a couple of local wine bars below the Montmartre near the Gare du Nord.

Get one of the DK Eyewitness guidebooks to Paris.
They have mapped out walking routes of some neighbourhoods you wouldn't necessarily think of.
Photocopy, and go exploring!
And get a Navigo Card for transport so that you can ride about, and get off where it looks interesting.

A couple thoughts that are not "unknown" but perhaps less commonly seen on a first-time visit would be the Fair Arts Museum in Bercy (fun because you get to ride some of the carrousels / interact with games), the Grand Mosque of Paris (beautiful!), and the Quai Branly Museum. I finally got to see all three on my most recent trip to Paris and enjoyed each of them.

Edith Piaf nights at Le Vieux Belleville. The singer and musician play her songs, get interactive with the crowd and you have a nice meal while listening.
https://www.le-vieux-belleville.com/en/program/

Thank you everyone for so many great ideas

The Dog Cemetery (Cimetière des Chiens) is a novelty, with pets buried in elaborate tombs similar to what their masters would like. This far-west-side park is the last resting place of Rin Tin Tin -- yes, the famous movie dog was an immigrant to the US.
Images here, but French text:

https://asnieres-sur-seine.fr/?s=Cimeti%C3%A8re+des+Chiens

Also try Wikipedia.

One thing that is on my list for my upcoming trip that I have not seen mentioned on this forum is the velodrome d'Hiver monument. It is near the Bir-Hakeim metro stop. It is a monument commemorating the round up of over 13,000 Jews, including children, in July, 1942. They were transferred to Auschwitz and only 400 survived.

A personal favorite of mine is to grab a picnic lunch (usually a sandwich and drink) and eat it at Arenes de Lutece. It's a park built around the Roman Arena from the time Paris was the Roman city Lutetia. If you go at lunchtime, you will sit in the original arena seating with many Parisian office workers (also eating their sandwiches). On the floor of the arena, there are likely to be older gents playing boules and/or some school kids kicking around a football. It's free, relaxing and, so far, a local hang out only.

http://bit.ly/2UMy0nq

Browse Deyrolle, the wonderful taxidermy shop at 46 rue du Bac (upstairs).
Beautiful, unique, and interesting.

In the Bois du Boulogne we rented a rowboat and paddled around for a while-had a blast and I'm pretty certain we were the only Americans on the Lake that day (note 50 Euro cash deposit, plus rental, in the warmer months). We did this and the Museum of Counterfeits on the same day as they are close to each other in the 16th.

Here's my photos of both from the day, and at Les Cocottes for dinner.

https://thecedarchest.smugmug.com/Paris-With-a-Stop-in-Beaune-20/i-q4P9dq6

Also-the Paris sewer tour was quite interesting as well, I believe it's open again after a remodel.