I found this bit on Towarnicki's critical role in disseminating Heidegger's way of thinking.

While Towarnicki was in Paris, Heidegger read Being and Nothingness. He was impressed with Sartre's use of phenomenological description, and in reading Sartre's philosophical opus Heidegger came to understand the association between his philosophical work and French existentialism. To Heidegger, Sartre's emphasis on the human actor and the conservation of the Cartesian ego cogito was a misreading of his work. As a result, he was impatient to meet Sartre and discuss the discrepancies between their philosophical programs. When Towarnicki returned from Paris, Heidegger set out to instruct him about the fundamental differences between his philosophical project and Sartre's existentialism. Heidegger explained to Towarnicki that, unlike Sartre in Being and Nothingness, he in Being and Time had been interested solely in the question of being. "And that question was not an anthropological interrogation of human experience or the foundations for an ethics, but the question into the truth of Being in itself."

During this visit, Heidegger also tried to explain what he saw as the problems with the French presentation of Dasein:

Heidegger smiled with a perplexed air, then he started to laugh: "You philosophize on the ground like the Greeks." No. Dasein is not the cogito, the world is not inside of consciousness. Dasein does not mean "There I am"; it is more like "there." Heidegger pointed to a grove of magnolias at the edge of the park. He explained to me that Dasein is (Being) in the world.

Heidegger's presentation of his philosophy was nothing like the first reading of his work in France; Heidegger's concerns were seperate from those of Sartre's existentialism. Towarnicki returned to Paris ready to spread this information.

P. 165-166

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