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The Ultimate Guide to Paris Underground [2021] by Locals

2021 France Travel Update

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Paris Underground City

Paris really is a tale of two cities. There is the City of Light, above ground, with its beloved Eiffel Tower or the Louvre Museum. This is the city that the world sees and loves. But there is also a secret Paris underground city, lesser-known by visitors and locals, which is more than the Paris Catacombs.

Indeed, there are at least 130 kilometers of Paris underground tunnels and secret places, and it is possible to explore some of them through exciting Paris underground tours. Most of these tours are also a great way to learn lesser-known parts of the history of Paris.

Here’s the list of the best sites underground Paris, completed with some really cool Paris underground tours and visits. From Roman Lutetia (Paris’ first settlement) to the current metro of Paris, there is something for every taste.

Paris Underground Guide

Underground Paris Map

On the map of Paris underground, we have located all the Paris underground tours and visits described in the Paris Underground Guide. As you can see on the map, the Paris underground city covers most of the Arrondissements of Paris!

Click here to view the Underground Paris Map on Google

Best Paris Underground Tours and Visits

1.Paris Catacombs Tour

Catacombs of Paris

The Catacombs of Paris are 15th-century underground quarries reused years later for stocking the bones of disappeared cemeteries in Paris.

The Paris Catacombs tour explores some of these Paris tunnels and halls decorated with bones from the Middle Ages. This is the most popular Paris underground tour probably for its spooky side and an excellent activity for those rainy days in Paris or when it’s too hot outside.

The long lines to access the Paris Catacombs with a regular ticket are famous, so a Catacombs skip-the-line ticket or guided tour is key to avoid wasting your time waiting in line. We recommend this Catacombs skip-the-line guided tour, which is entertaining, and it gives access to secret halls closed to the general public.

2. La Petite Ceinture

Petite Ceinture Paris

The Petite Ceinture of Paris (the Little Belt railway around Paris) was a 32 km railroad line that circumnavigated the city developed during the 19th century.

Originally built to transport material goods from depot yards to the core of Paris, La Petite Ceinture became, since 1862, also a service for passengers. This little train stopped operating in the ’70s when the Parisian metro became popular. 

Today some sections of La Petite Ceinture are converted into green spaces opened to the public. It is possible to cross Paris underground in some places, walking on the rails of La Petite Ceinture.

3. Visit The Medieval Louvre Underground

Medieval Louvre

Known as the world’s most visited museum, the Louvre Museum was a Royal Palace home to the French Kings and Queens for many centuries.

The Palace of the Louvre has a long history that goes back to medieval times. The construction of the Louvre started in the 12th century under the rule of King Philippe Auguste, who wanted to protect Paris better before leaving for the crusades. At that time, the Louvre was a small medieval castle, part of the fortress protecting the city.

Over the centuries, this formerly medieval castle was enlarged and embellished by King Philippe Auguste’s successors, and we still can visit some of those remains in the Louvre underground.

After a great mise en scène work, today, people visiting the Louvre can see some parts of the medieval Louvre such as the fortress’ foundations, the moat, and some remains of the defensive towers. Click here to buy your Louvre skip-the-line tickets.

4. Explore Roman Lutetia in the Archaeological Crypt of Paris

Archaeological Crypt Paris

The Archaeological Crypt is a fascinating place located just in front of Notre Dame. Despite its proximity to one of the most visited monuments in Paris, the Crypt sees few visitors a day!

The place was supposed to be an underground car park until the excavation works uncovered one of the most well-kept parts of Roman Lutetia (4th century AD).

Today, the Archaeological Crypt is an excellent place to learn about the history of Lutetia, its Gallic predecessors (the Parisii). Visitors can also explore a part of the Roman Paris underground city: streets, public baths, and even a section of the Roman harbor along the Seine!

The picture above shows part of the public baths, a pool, and a section of the Roman walls.

TIP: The entrance to the Archaeological Crypt is included in the Paris Museum Pass! Check out our Paris Museum Pass review here.

5. Learn about Water in Paris with the Paris Sewer Tour

Paris Sewer Museum

The Paris Sewer Museum is a fascinating place located in the 7th district of Paris that details the history of the sewer system and water in Paris from the former Roman Lutetia to its modern layout (19th century).

The museum also explains the sewer workers’ role and water treatment methods, with interesting anecdotes about water in Paris. We were happy to know that Paris is the city with the biggest and most modern sewer system in the world!

The Paris Sewer Museum has been closed for a long time due to renovation works. It is expected to re-open its doors in 2021, so don’t miss this renovated museum if you are in Paris!

Hopefully, this Paris underground through the sewer system will resume soon too. Walk through these fascinating underground tunnels in Paris used to inspect the city’s sewing system and learn the secrets of this underground world that manages the city’s water supply and protects it from flooding of the River Seine.

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6. Visit Roman Lutetia’s Sewer System

Roman Lutetia Paris

The Romans of Lutetia also had an efficient sewer system different from the current sewer system and you can see a part of it just below the Roman baths inside the Cluny Museum, in the 5th Arrondissement of Paris.

These Roman Paris tunnels can be visited only during special guided visits by one of the museum’s curators. The visits are in French, but even if you don’t speak the language, the opportunity to see this Paris hidden gem is well worth it. You can check the museum’s scheduled guided tours here.

7. Navigate the Underground Sections of Canal Saint-Martin

Underground Paris - Canal Saint Martin
Photo Courtesy: @Marin d’Eau Douce

Napoleon I ‘s engineers designed the Canal Saint-Martin in the 19th century to bring drinking water to Paris. The Canal connects the Bassin de la Villette to the Seine upstream with a drop of twenty-five meters.

Canal Saint-Martin has nine locks and two swing bridges, and it measures 4.5 km long, more than 2 km of which flows underground. The Canal’s underground section is covered by a vault, which was illuminated every year by the Japanese artist Keiichi Tahara at the passage of the cruise boats.

This part of the canal is also frequently used for shooting films: movies like Ratatouille, Queen Margot, or Last Mission Impossible shot some of their scenes under Canal Saint-Martin’s vaults.

You can explore this fascinating area of underground Paris by booking a Paris canal tour. This beautiful boat tour from La Villette to Port de l’Arsenal is a great alternative to the classic Seine river cruises.

 8. Learn about Palais Garnier’s Secret Underground Lake

Opera Garnier in Paris

The underground lake below the grounds of the Opéra de Garnier is, in our opinion, the best secret of Paris underground!

Gaston Leroux’s tales in his novel The Phantom of the Opera were just stories?

In the book, Erik the phantom is a deformed architect who helped build the Opera of Paris. At the same time, he secretly built a magnificent palace below the Opera’s grounds for himself, surrounded by a vast subterranean lake.

This lake really exists, and it is located exactly below the opera scenario. Yes: somehow, the ballet dancers are dancing over the water!

When the opera’s foundation works started in 1852, the architects realized they were digging into a marshy area where the groundwater was very high. The Opera’s main architect, Charles Garnier, had the idea of incorporating a cistern into his design to redistribute the water and relieve the water pressure on the basement walls. The cistern is usually full of water, like a lake, to be used by the firemen in case of fire.

Unfortunately, only a few people have access to this subterranean lake, but you can explore it virtually here.

There are many fascinating mysteries and legends around the city’s beautiful Opera Theater, and you can learn about them with this Opera de Garnier tour with an expert guide.

9. Carrières des Capucins, Locals’ Favorite Paris Underground Tour

Carrières des Capucins

The famous Paris Catacombs only represent 0.5% of the Paris underground city. There are other places that are less easy to reach, sometimes forbidden places, which years ago were the object of clandestine parties and other meetings.

The Carrières des Capucins (the Quarries of the Capuchins) is a great, more local alternative to the Paris Catacombs. This limestone quarry located below the districts of Paris 14, Paris 13, and Paris 5 is maintained and enhanced by a non-profit association under the form of a museum.

This unusual and rather confidential torchlight underground tour unveils part of the city’s exceptional industrial heritage (the world of underground quarries) and some interesting curiosities. This tour (in French) is also a step back in time: indeed, under the streets of the 21st century, the Paris of the 18th century still exists inside the Capuchins’ old quarries.

10. The Metro’s Phantom Stations

Secret Paris Metro

With a daily ridership of 4.16 million (2015), the Parisian Metro is the most known part of the underground Paris. The metro of Paris has 300 stations spread all over the city, and there are beautiful metro stations that you can visit with a single metro ticket.

The Parisian Metro also counts 18 phantom stations, metro stations that were abandoned for different reasons. Porte des Lilas is the most popular phantom station because it is used to shoot movies. Metro scenes like the one in Amélie Poulain were shot at Porte des Lilas.

However, our favorite phantom metro station is Saint-Martin. Located in the 2nd arrondissement in Paris, this station was closed after the Second World War because it was very close to the (bigger) metro station Strasbourg-Saint Denis.

Saint-Martin metro station can only be visited during special occasions. The RATP, in charge of the public transportation system in Paris, organizes these guided tours.

Saint-Martin metro station is a step back in time. It still keeps the aesthetics, and ceramic decoration of the 30’s when it was still working, and its advertising panels still display the products of that time. Because Saint Martin is the saint patron of ceramic workers, these workers executed an awesome ceramic decoration with raised motifs for this station.

11. WW2 Bunkers

Paris underground bunker WWII

During World War 2, the city built underground bunkers to provide ‘a place to retreat for citizens in case of an air attack’. Some of these bunkers are still intact, and they are an interesting place to visit, a reminder of a sad chapter of Europe’s past.

The most famous underground bunker in Paris is located under Gare de l’Est, (open to the public on rare cultural occasions), and the bunker located under Champ-de-Mars, next to the Eiffel Tower under the southern pier.

Easier to visit are the bunkers of the Carrières des Capucins and the bunker 20m below the grounds of the Museum of the Liberation of Paris (point #11 on the map). Inaugurated on the occasion of the 75th anniversary of the Liberation of Paris in 2019, this museum is one of the most interesting free museums in Paris. The visit includes the underground command station of Colonel Rol-Tanguy, head of the Paris branch of the French Forces of the Interior.

12. La Maison du Fontainier and its Distribution Pools

La Maison du Fontainier Paris

During the 17th century, King Henry IV of France ordered to build a new aqueduct to bring water to the Left Bank of Paris. This new aqueduct, known as Aqueduct Médicis, was 13 kilometers long and could be accessed through 27 different inspection chambers called regards.

Chamber #27, also called Grand Regard de l’Observatoire, was the inspection chamber at the aqueduct’s end. Above it, a little house for the waters inspector or Fontainier was built.

What is interesting about this place is what happens below the house’s grounds. At this point, the waters of the aqueduct were finally collected before being distributed to the city.

The house’s grounds were divided into three different vaulted halls, each with its own distribution pool. The King’s distribution pool, with the water for the use of the King, was obviously the biggest. Then, there was a second distribution pool for the religious communities. Finally, the third distribution pool (the smallest) brought water for the rest of the population in Pais.

Later in 1845, the engineers Lefort and Mary built a large reservoir hall to store the overflow of water that drains at night. This tank-hall is connected to the old distribution pools through a large pipe. Crossing the pipe from the old distribution pools to the tank hall is the most celebrated part of the guided visit, especially for kids.

In the picture above, you can see the arrival of water from the aqueduct to the distribution pool for the religious communities. La Maison du Fontainier can be visited during special cultural events like Les Journées du Patrimoine in September.

13. Le Regard de La Lanterne

Underground Tunnels in Paris - Regard de la Lanterne

The aqueducts of Paris could be inspected thanks to different inspection chambers called regards. Today 18 ancient regards still exist in the city, but only eight are visible on the surface.

Among them, Le Regard de La Lanterne is the most beautiful. This cylindrical, stone building located in Paris 19 was built during the 16th or 17th century as the main inspection chamber for Belleville’s Aqueduct. This aqueduct brought the past water from the hills in Belleville to the Right Bank of Paris.

Paris Underground Tunnels - Regard de la Lanterne

This little regard that looks like a stone mushroom is covered by a dome surmounted by a lantern, which allows the circulation of fresh air inside. Some stone steps allow visitors to descend to the bottom of the well and get a glimpse of the underground tunnels that brought the water to central Paris.

Today this regard has no longer any technical function, but it continues to receive water from the Belleville water table.

14. The Montsouris Water Reservoir

Eau de Paris - Reservoir de Montsouris

This water reservoir was designed by the engineer Eugène Belgrand, the father of the current sewer system in Paris, between 1868 and 1873 to feed the southern part of Paris with drinkable water.

This is definitely the most awesome site of underground Paris, which looks like a beautiful underground cathedral with arched stone walkways in every direction and filled with turquoise water. You can see more pictures of this spectacular site here.

Unfortunately, the Montsouris Water Reservoir, located in the 14th Arrondissement of Paris, is classed as a ‘sensitive site’ (this is an important water storage unit for the city), and guided visits are today sporadic.

So there you have it, our selection of the best underground Paris tours and visits. Which Paris underground site would you like to explore right now?

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  • Paige W
    02/14/2018 at 4:56 am

    What a great guide to the Paris Underground. I had no idea that you could explore so much of their underground! The water reservoir looks interesting and spooky all at once.

    • WorldInParis
      02/15/2018 at 3:50 pm

      Yes, the water reservoir is a very cool place. Actually all those places are very cool 😉

  • Sandy N Vyjay
    02/13/2018 at 5:59 pm

    The subterranean world of Paris is indeed fascinating. 130 Kilometres of sights and experiences below the ground is really intriguing. The hidden metro stations and the sewer museum are something that attracts me immediately. Hope to be able to cover these below the ground attractions when we are there next.

  • Indrani
    02/12/2018 at 12:24 pm

    I regret not doing this tour while in Paris. The whole underground network is so amazing.!
    Catacombs tour seems so interesting. And your pictures have a mysterious effect.

    • WorldInParis
      02/15/2018 at 3:51 pm

      Well, some of the places listed on the post are opened only during special occasions. If you want to do the Catacombs tour, I suggest to book in advance

  • Jody Robbins
    02/12/2018 at 1:10 am

    This really is secret Paris. I had no idea there were so many underground tours you could take. I’ve been to Paris 18 times but never any of these sites. Next time!

  • Carol Colborn
    02/11/2018 at 5:54 pm

    Looking at the photos, I can almost feel the cold and dampness. Thanks for the tips. This is the most comprehensive post on underground Paris I have seen. And it is amazing how extensive it is!

    • WorldInParis
      02/11/2018 at 8:11 pm

      I suffered the humidity a little bit at Carrières des Capucins because it is a long tour. That’s why I recommend an extra layer even if it is summer above. And a hot coffee in a thermos also comes in handy 😉

  • Medha Verma
    02/11/2018 at 1:16 pm

    I am not surprised that I have not heard of most of these places (except Catacombs, I’ve been there) and that’s the whole point about travelling with a local, these kind of hidden gems that tourists don’t hear of, can only be known by the locals! The St Martin Canal and the reservoir look pretty awesome. A trip to Carrières des Capucins is also right up my alley!

    • WorldInParis
      02/15/2018 at 3:52 pm

      Hope you will make it, Medha 🙂

  • Claire
    02/11/2018 at 1:16 pm

    That’s actually a really good idea to use an abandoned metro station for filming – it saves closing down one of the others! I love the 30s decor at the Saint-Martin station too. I had no idea there was so much going on underground in Paris! I’d heard about the catacombs before, and although that would be interesting I don’t think I could handle being underground with all the skeletons!

    • WorldInParis
      02/11/2018 at 8:08 pm

      Oh, don’t worry for the skeletons, they won’t bother you! 😉

  • Anu
    02/11/2018 at 6:01 am

    I was aware of the Catacombs tours ut rest of everything you say is an education. I love studying water management systems in ancient cities, so it is good to know of the underground sewage systems, tanks, and lakes. It seems Paris underground is as incredible as the city itself.

    • WorldInParis
      02/11/2018 at 8:08 pm

      Yes it is! And even more fascinating to explore than the city above 😉

  • Tanvi
    02/11/2018 at 4:27 am

    I didn’t know that Paris has an underground world like that.. I’d love to go to the museum of water & the catacombs..This post is bookmarked!

  • Brianna
    02/10/2018 at 10:12 pm

    I of course had heard of the famous catacombs in Paris but i had no idea there was over 130km of underground to explore. With secret metro stations and ancient Roman waterways it really is likes a while other world.