The interior of the Four Seasons restaurant, a vision of Modernist elegance with its French walnut paneling and white marble pool of bubbling water, should not be changed, New York City’s Landmarks Preservation Commission decided on Tuesday.

The decision was a setback to Aby J. Rosen, the owner of the Seagram Building, which is home to the restaurant. Mr. Rosen had proposed what he characterized as minor changes to the interior that was designed by Ludwig Mies van der Rohe and Philip Johnson in 1958.