This article focuses on the influence of the (educational) policy of the Third Republic and the specific conceptions of citizenship that were implied in the reshaping of primary education. Particular attention will be drawn to the way children, as future citizens, were being addressed and ‘moulded’ through the then popular education practices, against the background of a severe assimilationist language policy and a fierce battle against religious institutions. One of its consequences certainly concerns the non-recognition, educationally as well as politically, of the problem of ‘immigrants’. The expansive definition of French citizenship vis-à-vis immigrants, with strong roots in the jus soli approach, implied that no special educational measures were taken to ‘adapt’ the Flemish, non-native speakers to their new situation, while at the same time a number of pragmatic motives on the part of the (children of) migrants themselves strengthened their integration and assimilation.