The house style produced by Maximilien Vox in 1938 for the Paris-Lyon-Méditerranée railway, and again in 1942 for French national railways (SNCF), are considered to be the first documents of their kind in France.
Their function was to standardise typefaces and layout of documents and signage, in order to reinforce the identity of the company. The guidelines were hardly draconian; they did not, for example, insist on a single uniform typeface.