“The contemporary world has undergone a number of upheavals, perhaps the most significant of which are those relating to population. These upheavals, although a priori falling within the field of demography, have transcended this discipline by questioning the paradigms of economists, political scientists, sociologists and beyond”. So begins a study by the École Nationale de la Statistique et de l’Administration Économique [National School of Statistics and Economic A – ENSAE].