As part of the reorganization, the museum hopes to do more than better manage the flow of its 6.6 million annual visitors, half of them foreigners. It also wants the painting to be understood in its historical and artistic context and not merely as another "must see" of Paris.

As a result, in the Salle des États, the tiny "Mona Lisa" -- just 30.3 by 21.7 inches -- now hangs opposite Veronese's monumental "Marriage at Cana" -- 32.6 by 22.2 feet -- and is accompanied by 52 works from the Venetian Renaissance, including paintings by Titian, Bassano, Tintoretto and Lotto, and others by Veronese. The Louvre has turned the gallery into the highlight of its extraordinary Italian collection.

But it was above all the magical appeal of the "Mona Lisa," and the fact that 2.5 percent of the Louvre's visitors are Japanese, that prompted Nippon Television of Japan to pay the $6.2 million cost of renovating the gallery. The network, which financed the cleaning of the ceiling of the Sistine Chapel in the 1980's, has also committed $2.2 million to upgrading the Louvre gallery displaying the "Venus de Milo."

Some of the changes inaugurated this week are subtle. For instance, while the "Mona Lisa" has been protected by glass since 1960, the painting has now been installed in a new sealed enclosure, behind 1.52-inch-thick glass, and at a permanent temperature of 43 degrees Fahrenheit and 50 percent humidity. A tiny spotlight on a shelf in front of the painting compensates for reflection and brings out colors that were lost in the somber display of the past.

As important, the move has offered occasion for a new in-depth study of the "Mona Lisa's" health, with the government-run French Museums' Center for Research and Restoration reporting that the painting shows no new evidence of deterioration. It said that the thin wood panel that Leonardo used remains slightly warped, that the work's surface is in good condition and that a 4.3-inch crack stretching from the top of the work to the model's hair has not grown.