And i mean as a business. I'm asking because I've been working in the industry for over a decade as a pastry/baker/cook. None of the chefs I've worked with gave a straight answer. One said Italy, but he's an asshole and one said France but he's a raging alcoholic. Tried to google to no avail. Please and thank you.
If we're talking about a modern restaurant, according to Guide Gourmand de la France it is credited to Boulangers in Paris in what is now Rue du Louvre in 1765., although this has been disputed. Rebecca Spang in 'The Invention of the Restaurant", credits it to Mathurin Roze de Chantoiseau in Paris, 1766.