Lamarck - Caulaincourt (lamark colɛ̃kuʁ) is a station on Line 12 of the Paris Métro in the Montmartre district and the 18th arrondissement of Paris.
Lamarck - Caulaincourt is located in within the 18th arrondissement of Paris, which covers some of the northern-most parts of the city. Specifically, it runs beneath Rue de la Fontaine du But where it changes into a staircase. The station takes its name from the two main roads that cross near its entrance: Rue Lamarck and Rue Caulaincourt.
The station opened on 31 October 1912 as part of a northward extension of the Nord-Sud company's Line A from Pigalle to Jules Joffrin. In 1930, the Compagnie du chemin de fer métropolitain de Paris (CMP) bought out the Nord-Sud company and renamed Line A to Line 12 in order to conform to the former's convention.