RESTAURATEUR, noun, he or she who repairs or re-establishes.
It is rarely used, except in cities and public monuments.
This city has been ruined, and the prince rebuilt it. He is its restaurateur.
Restaurateur is also used for a cook-caterer who provides food at all hours, the type and price of which are indicated on a sort of placard, and which are served by the portion.
To have dinner at a restaurateur's; the menu of a restaurateur.

DICTIONNAIRE DE L'ACADEMIE FRANCAISE (SIXTH EDITION, 1835)

The Invention of the Restaurant - Paris and Modern Gastronomic Culture. Rebecca L. Spang. First Harvard University Press 2001