Peter Lavroff was a 19th-century Russian revolutionary, philosopher, sociologist, and theorist of narodism. He wrote the lyrics to the "Worker's Marseillaise".
He was a secular Jew. He entered a military academy and graduated in 1842 as an army officer. He was good at natural science, history, logic, philosophy, and psychology, and he taught mathematics for 20 years.
He joined the revolutionary movement as a radical in 1862, though he was exiled to the Ural Mountains for that six years later. Eventually he escaped to Paris, France, where he became a member of the Anthropological Society. He became a socialist. He became a member of the Ternes section of the International Workingmen's Association in 1870, and a member of the Paris Commune.
In November 1872, he arrived in Zürich, Switzerland. Lavroff tended more toward reform than revolution, or at least he saw reform as salutary. He preached against the conspiratorial ideology of Peter Tkachev (and others like him). Lavroff believed that while a coup d'état would be easy in Russia, the creation of a socialist society needed to involve the Russian masses.
He died in Paris on 6 February 1900.