We walked along the Canal Saint-Martin, an artificial waterway that Napoleon had built in 1802, so fresh water would be available to support the growing population and avoid diseases. The canal, funded by a new tax on wine, was completed in 1825.
The canal is 4.5 km long and connects the Canal de l’Ourcq to the Seine. Two streets run parallel to the canal; the Quai de Valmy and the Quai de Jemmapes. On Sundays the streets close so that pedestrians and cyclists can safely enjoy the area.
In 1848, rioters had taken refuge on the east side of the canal knowing that government troops had limited access into the Faubourg (suburb) Saint-Antoine. During Haussmannization, part of the canal was paved over to form the Boulevard Richard-Lenoir in the 11th Arrondissement. This also allowed for better military access to the area.
Part of the canal is underground between the Bastille and Republique metros. Above the opening of the underground canal, in the 10th arrondissement is the Square Frederick-Lemaitre. Frédérick Lemaitre, born Antoine Louis Prosper Lemaître (July 28, 1800-January 26, 1876) was a French actor and playwright, known for his comedy. Throughout Paris you see monuments and plaques that highlight the history of the area, little bits of the culture that make you want to know more.
This area was considered a working class area during the 19th century. 
Now you see more professionals and students moving into the area, in search of reasonable apartments; and a different sense of community.
Along the canal are restaurants and bars where people watch the barges go through the series of locks that raise and lower the water level so that barges can move up or down stream.
A series of foot bridges allow you to cross the canal, and the Pont Levant de la rue de Crimee or Pont de Flandre raises when boats need to go under.
This area has fewer tourists, and the restaurant staff are less likely to speak any English. There was also a lot more graffiti on the walls and buildings. Since I don’t know a lot about street art or graffiti, I’m not sure if this area had more graffiti as a form of artistic expression or of making social comments and being heard. In the higher tourist areas of Paris, the city removes the graffiti daily. The types of stores and shops were also different from the higher tourist areas. These stores seem geared more for the local people. It was a very comfortable and quiet neighborhood. You can relax and just enjoy the sights around you without dodging a lot of people.
While films were not actually shot in Paris until the 1950s, in the 1930s, the Canal Saint-Martin was the site of Marcel Carne’s film Hotel du Nord which portrayed the city as a haunting, unchanging place that had little to offer the working class and focused on working class crime.
The canal also appears in Amelie, the 2001 film by Jean-Pierre Jeunet, in which Amelie skips stones at the locks of the canal. But, Amelie is another story for later.