What is the proper noun of restaurant?

There is no single proper noun for "restaurant". A proper noun is a specific name for a person, place, or thing.

To get a proper noun for a restaurant, you need to provide the name of the specific restaurant.

For example:

* The Red Lobster is a proper noun referring to a specific restaurant chain.

* Chez Panisse is a proper noun referring to a specific restaurant in Berkeley, California.

Let me know if you have a specific restaurant in mind and I can tell you the proper noun for it!