Above picture shows the cover
of an officila French phonebook from 1953.
It coverts Aube of the the French Departments.
At this time Roger Duchet was the French Minister of PTT.
The Annuaire mentions that
"Seul ... L´Office d´Annonces"
"Only the Office d´Annonces was selling ads in the phonebook".
Working as a Monopoly was indeed very profitable.
At the time Office d´Annonces
was located in a beautiful Building
in center of Paris 36 rue de Vivienne
near the French Stockexchange.