Paris’s city council adopted engineer Fulgence Bienvenüe’s plan for a citywide underground railway. This decision set the basic network logic—fast east–west and north–south lines with connections—used to guide early construction.
The French state declared the first six Métro lines to be of “public utility,” a legal step that allowed land use, permits, and major works to proceed. It marked the formal start of the construction era for the initial network.
Work began on what became Line 1, using largely cut-and-cover construction (digging from the street and then covering). This was the practical beginning of the Paris Métro as a built system, not just a plan.
The first Métro service opened between Porte de Vincennes and Porte Maillot, timed to help move crowds for the Paris Exposition. It proved rapid transit could work in Paris and created pressure to expand quickly.
The first section of Line 2 (then “2 Nord”) opened, starting the idea of linking outer boulevards and major hubs on the Right Bank. Its mix of underground and elevated segments expanded the Métro’s construction playbook.
A short circuit caused a deadly fire on Line 2 that killed dozens of passengers. In response, the network adopted stronger safety practices, including better separation of power and lighting circuits and improved station exits.
Line 3 opened between Villiers and Père Lachaise, adding another major east–west route north of Line 1. This helped spread demand across multiple corridors and supported denser service in growing neighborhoods.
Line 5’s first section opened from Place d’Italie to Gare d’Orléans (now Gare d’Austerlitz). It included the Austerlitz viaduct over the Seine, showing that the network could combine tunnels with major visible structures when needed.
Line 4 opened between Porte de Clignancourt and Châtelet, starting the key north–south spine through central Paris. The line’s next challenge was connecting across the Seine underground, a difficult engineering step for the time.
A new tunnel linked Line 4’s northern and southern sections between Châtelet and Raspail. This created a continuous north–south route and demonstrated that the Métro could cross the river underground, enabling later central extensions.
The private Nord-Sud company opened its Line A from Porte de Versailles to Notre-Dame de Lorette. Nord-Sud introduced distinctive station design and created competition that shaped how Paris expanded and standardized the network later.
Nord-Sud opened Line B from Saint-Lazare to Porte de Saint-Ouen, adding another northwestern corridor to the fast-growing system. This expansion strengthened access to working-class and industrial areas beyond central Paris.
Line 3 extended to Porte des Lilas, with an associated shuttle link concept toward Pré-Saint-Gervais. The extension pushed the Métro deeper into the northeast and shows how planners experimented with branches and connecting services.
Line 9’s first section opened between Exelmans and Trocadéro, starting a large new route through western Paris. Interwar construction helped fill remaining gaps and increase capacity as the city’s population and travel needs grew.
Line 1 pushed beyond its original terminus at Porte de Vincennes to reach Château de Vincennes. This was part of a broader shift toward serving the suburbs, not only the city center.
Line 11 opened as a deep line connecting central Paris to the northeast, requiring complex construction under existing lines. It improved access to hillside neighborhoods and added resilience by giving riders another path into the center.
The line later known as the “old Line 14” opened between Bienvenüe and Porte de Vanves, reflecting the final phase of major prewar line-building. It was part of the Nord-Sud legacy after its absorption by the CMP, as the system moved toward unified management.
Line 1 extended from Porte Maillot to Pont de Neuilly, timed to strengthen access ahead of the 1937 Paris exposition period. The project continued the pattern of pushing the Métro outward to meet suburban growth.
At the start of World War II, the Métro reduced operations and closed some services, including the Porte des Lilas–Pré-Saint-Gervais shuttle. This moment marks the practical end of the 1898–1939 construction-and-extension era as the network shifted into wartime constraints.
Paris Métro construction and extensions (1898–1939)