Abstract
This article presents an epistemological and didactical analysis of curricular phenomena regarding the teaching of algorithmics in France in 2009-2019 in the mathematics curriculum of high school. Our study is based on the analysis of Algobox, a software designed for an introduction to algorithmics in coherence with the curriculum, and much used during this period. This software makes marked technical choices, whose consequences are questioned here. We show how the “project” embodied by AlgoBox runs up against conceptual and didactical difficulties.