In 1927, the French employers' organisation, CÈgos, named Lieutenant-Colonel Rimailho as head of a committee charged with the design of a uniform-costing method for all industry sectors. This method (known as the homogeneous sections method) became widely diffused through education channels and its encouragement in the successive French Accounting Plan. Rimailho's testimony and investigations carried out in various military archives show that this system was directly inspired by the experiments undertaken within the military manufacturing plants since the beginning of the twentieth century. This filiation confirms the importance of the role of military engineers in management history. Moreover, this study also reveals two significant aspects of the mechanisms of accounting innovation. First, a certain logic for justifying and legitimising might explain, beside technical and economic determinism, the search for new accounting systems. Second, to be improved and more widely used, a management tool needs a strong support network.