Demonstration of the relative educational ineffectiveness of doubling in order to remedy school difficulties during compulsory schooling is no longer to be done. For some 15 years, policies to combat repetition have been undertaken, particularly on the basis of this observation, in France, Canada (Québec), Switzerland, the canton of Geneva and French-speaking Belgium. The article looks at the resistance of these policies. On the basis of the reform of Belgian French-speaking lower secondary education, he presented an emblematic case of a mismatch between intentions and achievements in the fight against repetition. The relative failure of this reform makes teachers’ commitment to doubling. Refusing to reduce this attachment to a conservative or irrational reaction by teachers, the article argues that the legitimacy of repetition in the eyes of teachers is linked to the latent functions it performs within the school system (management of heterogeneity, location of establishments, regulation of the school system, professional autonomy). In conclusion, the article stresses the importance of building the conditions for plausibility of change in education, which require a pragmatic understanding of the reality of grassroots actors and consideration of institutional barriers to change.