In our liberal democracies, everyone has equal rights and equal weight in terms of participating in the exercise of power. Gone are the days of census suffrage when, in France and other European countries, the right to vote was granted only to citizens who paid tax above a certain threshold, and women did not have the right to vote. Is this truly the case, though? The provocative expression “second-class citizenship” would suggest otherwise! Indeed, while officially, or from a legal point of view, we cannot talk about second-class citizenship, or secondary or sub-citizenship, what ought we to do when the actors themselves speak in such terms? What should we do with the conceptual tools created by social actors? By analyzing different contexts, we will show in this work that the implementation of the rights and duties of citizens, and the fundamental values of modern citizenship, appear to be in question. We use the expression “second-class citizenship” not only to refer to the power of the internalization of a hierarchy among citizens (accompanied by the experience of contempt), but also to forcefully reveal this inequality between citizens who are supposed to be equal before the law. Would it be possible to prevent this hierarchy and these inequalities? Other modalities can be considered in this liberation of the conditions of exercise of second-class citizenship, such as legal work, deepening of international relations, social work of proximity facilitating the integration of ethnic minorities, etc. However, in our view, education is a particularly powerful political means to give substance to citizenship.