The (establishing) shot used as the 'best French restaurant in Minneapolis', as Karl has been told, is actually New York City's iconic Four Seasons restaurant, located at 99 East 52nd St., which had been in existence since the late 1950s. It closed on July 26, 2016.
Eric Braeden later revealed that Karl Heller was based on the caustic reviewer, John Simon.
Eric Braeden played a similarly caustic Broadway critic in "The Nanny" episode "Sunday in the Park with Fran" (S1 Ep18)