The ideology spread by Stalin's agents...
... is exactly what dominates the Intelligentsia in France and other countries.
You do not endorse Stalin. You do not call yourself a communist. You do not declare your love for the regime. You do not call on people to support the Soviets. Ever. Under any circumstances. You claim to be an independent-minded idealist. You don't understand politics, but you think the little guy is getting a lousy break. You believe in open-mindedness. You are shocked, frightened by what is going on right here in our own country. You are frightened by the racism, by the oppression of the working man. You think that the Russians are trying a great human experiment, and you hope it works. You believe in peace. You yearn for international understanding. You hate fascism. You think the capitalist system is corrupt. You say it over and over again and you say nothing, nothing more.
Double Lives: Spies and Writers in the Secret Soviet War of Ideas against the West by Stephen Koch
Of course, Stalin also had more obvious agents.