This article analyses the involvement of the social-democrat Friedrich Ebert Foundation in Poland in the context of the Ostpolitik. Based on German and Polish unexplored archives, as well as on interviews, the contribution is an attempt of a "histoire croisée" of the German-Polish relations during the ultimate phase of the Cold War. It focuses as well on the macropolitical context as on interpersonal exchanges and trajectories. The analysed affinities and tensions help to understand better the situation in 1989, which was not a Stunde Null of bilateral relations.