Boulanger

All types of restaurants have in common that their existence is relatively new. Larouse Gastronomique Encyclopedia of Food Wine and Cookery says: In 1765 a man named Boulanger, a vendor of soup in the Rue Bailleul, gave to his soups the name of r e s t a u r a n t s, i.e. restoratives, and inscribed on his sign: 'Boulanger sells magical restoratives', a notice which he embellished with a joke in culinary Latin: Venite ad me; vos qui stomacho laboratis et ego restaurabo vos.

The influence of Royal kitchens rushed down into the inns and taverns, especially during the days of eliminating royal households by means of the guillotine. Many a personal chef suddenly without an employer hit the street to make some sort of a living.
Nevertheless it's Boulanger who is credited with establishing the name restaurant.
Chad [quixote@imagin.net] added the following:
In the 16th century the word "restorative" had been used to describe rich and highly flavored soups and stews capable of restoring lost energy. The word "restaurant" is derived from the French word "restaurer" (to restore - presumably as in restore lost energy).
In the 16th, and up until the mid18th century all prepared foods that were to be sold were made by guilds who had a monopoly on certain food items.
"Rotisseurs" made roasted meats. "Patissiers" made poultry items, pies, and tarts. "Tamisiers" made breads. "Vinaigriers" made Sauces/stews (including "restoratives"). All that catered and organized feasts and celebrations were known as "Port-chapes".
In 1765 Monsieur Boulanger hung a sign on his tavern door advertising the sale of his special "restorative", which was a dish of sheep's fat in white sauce.
At the time nearly all taverns offered prepared dishes. The dishes were usually prepared off premises by the appropriate guild member, and taverns had little say in what the patrons would be served. Patrons of the taverns were served family style at a communal table. This was acceptable because the tavern's primary function was to provide lodging and drink - not food. Boulanger's tavern differed since his establishment provided prepared dishes on site and to order (meaning a variety of dishes) - the first "modern" restaurant. His clientele was not only patrons looking for lodging and drink, but included patrons that had a main interest in dinning!
Boulanger was forced to close his establishment because he was quickly taken to court in a lawsuit brought by the members of the guilds. They claimed that Boulanger was infringing on their exclusive right to sell prepared dishes. Thankfully Boulanger triumphed in court and later reopened.
After Boulanger's trial several other restaurants opened up in the succeeding decades.
Boulanger opened up the door to the modern restaurant.

First American Tavern