 His conception of a “plus grande France,” based on political autonomy and military obligation for all parts of the French Empire, is put forward in the concluding chapters of his book "Comment finit la Guerre".After the Allied victory, Mangin's 10th Army was sent to occupy the Rhineland.There, he became the focus of controversy due to his attempts to foster the establishment of a pro-French Rhenish Republic with the aim of separating it from Germany and thus denying Germany the West bank of the Rhine.