As I mentioned before, my inspiration to find "mathematical" places in Paris came from David Eugene Smith Historical-Mathematical Paris (The American Mathematical Monthly, Vol. 30, No. 3 (Mar. - Apr., 1923), pp. 107-113).
David Eugene Smith (1860-1944) was born in Cortland, NY, just a little more than 20 miles from Ithaca, where I live now. When he died, "the world lost one of the most colorful and influential figures in the fields of the history and teaching of mathematics".(in memorium). Prof. Smith travelled to lecture and to stay in Paris numerous times over the period of 40 years. He was a passionate collector of books, letters and various memorabilia of interest of math historian. From the letters he collected and other sources he learned the addresses of mathematicians in Paris. I was intrigued what I would be able to find 88 years later after his account of "historical-mathematical" Paris was published.
Prof. Smith suggested to start with the most ancient part of the city - the Lutetia, now a part of the Ile de la Cite, where Notre Dame stands. In the ancient Palais de Justice there is a little gem of Gothic architecture - Sainte Chapelle. One of its canons was Rollandus, who wrote a general treatise on mathematics c.1425, now this manuscript is in Plimpton Library, Columbia University, New York City.
There is no need to have a mathematical reason to visit Sainte Chapelle - some say it is the best Gothic architecture example. If you have a choice - go there on sunny day to enjoy the stained glass windows!
On the other side of the Palais de Justice it is possible to visit the most ancient prison of the city if interested to see Conciergerie.
The Notre-Dame Cathedral, mathematically, is most interesting for its Gothic arches and flying butresses.
the church of Saint-Julien-le-Pauvre.
"Consecrated in 1220, Saint-Julien-le-Pauvre was just nearing completion when the newly established University of Paris began setting up shop next door. And as the university had no buildings, this little church became its chapel and assembly hall. In the 1520's students rioted and trashed the church, so clergy banned firther assemblies. Albertus Magnus advocated for peacful coexistence os science and religion there and his student Thomas Aquinas lectured there (according D. Burke's book). David Smith mentions both of them lecturing in the convent of the Dominicans or Jacobins that from 1217 to 1790 used to be next to place where now is the Pantheon. There is a plague on the wall there too (currently it is the building of the library).
Hungarian Rapsody No.2. This was the first time I listen to it live in the concert sitting very close to this piano and watching Herbert du Plessis perform. (I was too shy to ask him how many times he had played this piece since his first performance at the age of 8.)
The Pantheon is neo-classic temple built on the highest point of the Latin Quarter. It is a place where French grandes hommes are burried (only two are women - Marie Curie and Sophie Berthelot). In 1851, physicist Léon Foucault demonstrated the rotation of the Earth by his experiment conducted in the Panthéon, by constructing a 67 meter Foucault pendulum beneath the central dome. Mathematicians Lagrange, Lazare Carnot, Paul Painleve , physicist Jean Perrin are burried there, and both Pierre and Marie Curie were enshrined in the crypt in April 1995. Gaspard Monge and Marquis de Condorcet were buried at the time of the bicentennial celebration of the French Revolution.
There is still a monument at Pere Lachese cemetery at the first burial place for Monge.
If you face the entrance of the Pantheon on the left behind it you see the Eglise Saint-Etienne-du Mont where Pascal is buried. Descartes was first buried here also but in 1819 his remains were transferred to the Eglise Saint-Germain-des-Pres.
In this alcove Pascal's neighbour is Racine, the name you will recognize if you are familiar with the history of theatre.
Ecole Politechnique, which was founded during the French Revolution by two mathematicians - Lazare Carnot and Gaspard Monge and has always been one of the most elite schools as one can see from the list of notable Ecole Politechnique alumni.
Le Pere Goriot, one of my required readings in high school. It was this area where young Ernest Hemingway with his wife Hadley had his first home in Paris.
Rue Rollins No. 14 is one of many addresses where Rene Descartes lived.
According David Smith Rue Rollins No.2 was the house of Marguerite Perier - Pascal's sister, and Blaise Pascal died there.
Place de la Contrescarpe I continue my walk on Rue Moufetard, famous ancient market street that has been featured in many literary works by the writers who enjoyed this lively area. It is getting dark, soon restaurants will start to open their door for diners, my thoughts are turning away from mathematical interests towards to the memories of literary descriptions of the area. Another mathematical walk will be next time.
p.s. I am adding here
Paris sites by J. Kiernan (1/26/99) which he posted on Historia Matematica mailing list in 1999.
A good place to begin is the Conservatoire des Arts et Metiers on
Boulevard de Sabastopol. The museum contains one of Pascal's original
adding machines. Near-by are the Archives National. Before you reach
the Seine you will pass Tour St. Jacques. Inside the tower there is
a statue of Pascal commemorating his experiments on air pressure.
To the right is the Louvre which contains a Frans Hals portrait of
Descartes and a Houdin statue of Pascal. As you cross the Seine at the Pont des Arts you will arrive at the Academie des Sciences. Take Rue Bonaparte to the Church of St. Germain de Pres. Inside there is a cenotaph dedicated to Descartes. Follow Boul. St. Germain to the inn La Procope and have the lunch special (if its not dinnertime yet!). In one direction you will find the birthplace of Sophie Germain. If you follow Rue M. de Prince to the end, at No. 54 you will find a plaque commemorating Pascal's (n-1)th domicile. Now follow Rue Sufflot to the Pantheon. Spend some time there. Behind the Pantheon is St. Etienne de Mont, Pascal's church. You will find two plaques and a bust inside. Behind the church is 16 Rue Rollin where Descartes once lived. Continue past Rue Monge to the Jardin des Plants. Inside you will find a statue of its curator, Buffon. Double back to Rue Monge and follow it to the Ecole Polytechnique, the home of an entire class of 19th Century mathematicians. Nearby is the
University including College de France, where Roberval taught, and the
Sorbonne. The University is one of the oldest in Europe and specialized in theology and logic.
On another day you may wish to start out at Port Royal, the refuge of Pascal, and walk to the Observatory which is only open to the public once a month by appointment. Behind the Place Denfert Rocherau there is the Hotel Sophie Germain. Nearby there is a market on Rue Daguerre. Walking down this rue you will pass Rue Gassendi and Rue Fermat. Make a left to Cimetiere de Montparnasse, the burial place of Poincare. On the other side of the cimetiere is Rue Huyghens.
If you visit the Tour Eiffel, you will find several plaques dedicated
to mathematicians. Nearby is 108 Rue de Bac where Laplace resided.
Across the Seine is the Palais de la Decouverte which has exhibits on the history of mathematics. Condorcet met his fate at Place de Concorde.
If you take the train just south of Paris to the suburb of Acueil, you will find many commemorations of Laplace. If you want to see his birthplace, you need to take a train from Gare St. Lazare to Pont L'Eveque. About 7 km away is the small town of Beaumont en Auge. You can walk it on a nice day.
The cathedral at Chartres is a living monument to education. On the West
Portal there are relief personifications of the seven liberal arts. These
include Pythagoras, Aristotle and Ptolemy. Take time to investigate the
circular maze inside the cathedral.