The article is devoted to the memoirs of the French politician, one of the founders and leaders of the SFIC - French Section of the Communist International, historian and publicist Boris Souvarine (1895-1984). Souvarine memoirs tell us about his first meeting with the Soviet Union in 1921, when a young French Communist came as a delegate of the III Comintern Congress and stayed for about three years. From this moment began the formation of Souvarine as a sharp and consistent critic of the Bolshevik regime and as a historian- sovietologist. The literary heritage of Souvarine is vast, but most part of his works, written in French, has not yet been translated and remains inaccessible to Russian readers. The article gives some facts about meetings of Souvarine and other French Communists with V. I. Lenin and his observations on the lives of Comintern employees. The article also discusses the features of Souvarine's historical method, in particular, the right of the historian to assess the events he had witnessed. According to this method Souvarine himself made a cardinal "revaluation of values". The feature of Souvarine's memoirs consists in a combination of a description of the events both as an eyewitness and as a historian able to assess these events in retrospect.