The Ireps Pays de la Loire has been actively involved in the use of psychosocial competencies (PSCs) for health promotion for the past 20 years. Three major phases have marked the history of this initiative. - The first phase involved building expertise in classroom-based interventions from 2001 to 2014 and formalizing these practices through the "Psychosocial Competencies Toolkit" website. - The second phase involved piloting a medium-scale rollout through the "En santé à l'école" program from 2015 to 2018, aimed at transferring skills to teachers. - The third phase focused on institutionalization through the Academic Program for Strengthening Social and Emotional Skills in the Classroom, led by the Nantes School District. The "Psychosocial Skills Toolkit," a resource website, offers both pedagogical and methodological tools to guide the implementation of projects and facilitate sessions dedicated to the subject. The authors’ intention was to provide the necessary components for developing projects that could incorporate criteria ensuring the quality of the initiatives, drawing at the time on available data from evaluations of programs recognized as effective. The “Cartable” is therefore a framework for interventions, still used as such today. The "En santé à l'école" program, launched in 2015 by the Regional Health Agency and led by Ireps Pays de la Loire, was implemented from 2015 to 2018 in partnership with the Nantes Academy and Uradel. This program took various forms, including support for professional practices in continuing education or initial training, and support for educational teams. An external evaluation concluded that the program was successful in terms of transferring skills to teachers and highlighted the factors that contributed to this success, including the institution’s commitment, the competence of the trainers, and the quality of the approach used: understanding the meaning of the activities by experiencing firsthand what they would have students experience is essential and requires dedicated training time (at least 12 hours). Following this experience, the Nantes Academy sought to integrate the strengthening of psychosocial skills into its academic plan. Since 2018, the Ireps Pays de la Loire has been responsible for supporting this integration. The academic initiative relies on internal coordination and the mobilization of national education staff, known as resource professionals; these individuals are trained by the Ireps Pays de la Loire to conduct training workshops for teachers in primary and secondary schools. The inclusion of the academic program within a pillar of the academic project aimed at improving the school climate provides a legitimate institutional framework but risks losing sight of the requirements related to health promotion. To counter this, support for the professional development of resource professionals is essential, requiring time to acquire the knowledge needed to intervene and guide professional practices related to CPS. Plans are currently underway to roll out 18 training courses benefiting more than 400 teachers during the 2020–2021 school year alone, with follow-up support for the trained teams over a two-year period. This initiative will therefore enable the scaling up of large-scale training efforts. However, it will be necessary to maintain a system for supervising resource professionals to ensure the effectiveness of their work, the evaluation of which has yet to be conducted.