Pottier was elected a member of the Paris municipal council - the Paris Commune, in March 1871. Following the Commune's defeat, in June 1871 he wrote the poem L'Internationale, which became the International Workingmen's Association anthem during its last years (1871–1876), and has been used by most socialist and leftist political internationals since. The Encyclopedia of Mass Persuasion deems the anthem "one of the best-known propaganda songs since La Marseillaise". After writing the poem, Pottier went into exile but later returned to France, dying penniless.
Fifteen years after the Communards were crushed in blood by the Versaillais (1871), Eugène Pottier dedicated the following hymn to their revolution:
During his exile in New York City (1873–1880), Eugène Pottier was received at Les Égalitaires lodge in New York. In his cover letter, he said that Freemasonry "is composed of a group of freethinkers who, having made a clean sweep on tradition and recognizing nothing superior to human reason, consciously dedicate themselves in search of Truth and Justice".