Every year, 260 children or babies with heart defects are in need of hyperspecialised surgery. However, there is currently no infrastructure for infant cardiac surgery in the France-Wallonia-Flanders cross-border area. Lille University Hospital wishes to meet this public health challenge by offering this care by 2020. The development of this infant cardiac surgery activity aims to improve the quality of life of the cross-border population, in particular by reducing the risks associated with the current transfers of these newborns to Paris and Brussels, for indefinite and sometimes long periods for families far from their place of residence. The University Hospital of Lille is partnering with one of the 3 Belgian centres in paediatric cardiology to launch the training of its professionals in order to reach the required level of expertise. The training course involves 28 French doctors and 48 paramedics who work alongside their Belgian colleagues to provide care for patients, including French patients. The two institutions also aim to create a European centre of excellence and joint research on congenital heart disease. The network of competence thus formed includes the health establishments on the Belgian side in its network, which benefit from the dynamics of knowledge dissemination. It also benefits from the employment dynamics generated by the creation of this new activity at Lille University Hospital.