A unique programme entitled the “Programme d’appui aux nouveaux arrivants” (PANA) exists in the Canadian majority Anglophone province of Ontario, within the minority French-language education system. This programme offers additional support to newcomer immigrant children who are undereducated and need assistance to catch up academically to their Canadian-born peers through a formal curriculum policy. This study linked the discussion of education policy as a means for collective identity construction to the fostering of a diverse and inclusive society, through analysis of the case of the PANA programme. It did so especially through the lens of the institutionalism inherent in the French-language education system. Policy analysis of the PANA formal curriculum documents, as well as qualitative interviews with actors at the provincial, regional and local levels of educational governance in the province, generated interesting reflections. Notably, institutionalism, while having a role in the PANA programme does not define it. This finding differed from the expectations of the study which were based on historical institutionalism and integration theories. The use of an abductive methodology revealed the existence of a complex web of actors involved in the governance of the PANA programme and its associated policy framework. These actors hold differing interpretations of the PANA programme and its relative importance when it comes to the dichotomy of collective identity construction and diversity and inclusion. Ultimately, local teachers, as the actors responsible for the implementation, are street-level bureaucrats who hold a high level of discretion within an opportunity transparent field, allowing for agency. They are, in fact, mandated to alter the programme to local demands through the concept of prudential curriculum, and adapt it to each child through ‘différenciation pédagogique’. This discretion is expressed by actors holding a broad range of understanding, training and motivation. While it does create some challenges, it is recommended that the potential flexibility within the institutional framework of the French-language education system be used to implement more training, standardisation and centralisation, and thus ensure a more consistent quality of the service provided through the PANA programme within the province.