The French word for a person who owns or runs a restaurant is restaurateur, with no n, and this is the spelling used most often in English, especially in edited writing.
Restauranteur, with an n, appears in English about once for every ten instances of restaurateur. But while this spelling is common and has a long history, many people consider it wrong.
The Oxford English Dictionary notes restauranteur as originally from the U.S. and lists examples from as far back as 1859, though a historical Google Books search covering the 19th century uncovers no more than a handful of instances of restauranteur. Many more examples are found in texts from the first half of the 20th century, including many from outside the U.S. Today, the misspelling appears about equally often throughout the English-speaking world.
See full article at http://grammarist.com/spelling/restaurateur