This article is about Daryl Siedentop's legacy and the reciprocal influences of his thinking on the French "didactique" research in physical education (PE). The introduction points out the deep knowledge of French PE Daryl Siedentop had gained through his international activities and how his theoretical and methodological contributions resonated and inspired the French "didactique" research. A first section presents some key links between the Sport Education model and the didactic approach in terms of curricular choices. The second section emphasizes the distinctive but complementary research perspectives of the classroom ecology and the joint action in didactics for the future of PE. The conclusion returns to Daryl Siedentop's ontological and epistemological viewpoints and their many common aspects with the French "didactique" tradition.