The Joint Comprehensive Plan of Action (JCPOA) is considered one of the turning points in the foreign policy of Iran and other countries involved in it, namely Russia, China, the United States, France, the United Kingdom, and Germany. The aim of this article is to examine Germany's role in this program, and therefore the question arises as to what roles Germany played at the "beginning" of the JCPOA negotiations, during the "during" the JCPOA negotiations, and in the "post-JCPOA" period, and what factors influenced these roles? The hypothesis of the article, which is examined using a qualitative method and a descriptive-analytical approach, is that Germany, by adopting a normative foreign policy in the post-Cold War period in accordance with the principles of Euro-centrism, trans-atlanticism, looking to the East, "greater responsibility," and at the same time having a significant trade relationship with Iran, entered the "JCPOA" and played a role in it in order to have a broader presence and more active participation in regional and international developments. The findings of the article showed that a country that has the necessary capacity to play a role in the global arena, if it is left aside at some point in history, will try to take over its old position by crossing the abyss, removing the taboos and providing the conditions, and will re-emerge as an influential unit in the international arena. By generalizing the issue to Germany, it is concluded that this country, which was considered a great power and an influential player in regional and global developments until World War II, has deviated from its position for some reasons and, with the end of the Cold War and the provision of conditions to play a role commensurate with its power on the global level, has entered the "Joint Comprehensive Plan of Action".