But it was. Not because of the flowers, though there were some (water lilies, which aren’t in the park at all except in the form of Monet’s “Water Lilies” in the Musée de l’Orangerie). But because what the park represents is also what, it turns out, Mr. Anderson is doing at Dior: taking a haven originally created as a private playground for the aristocracy and throwing it open to the public.