It was a Tuesday afternoon in April when I climbed the narrow staircase on Avenue Matignon. Paris lay bathed in that milky spring light that softens the boulevards and bathes the facades in an almost ethereal gentleness. I carried a bouquet of violets with me—not because I assumed Heine appreciated flowers, but because the woman on the corner of Rue du Faubourg Saint-Honoré had assured me they brought good luck.