Mounted by the Petit Palais in collaboration with the City of Paris’s Musée de la Vie Romantique, William Blake: The Visionary Genius of English Romanticism—featuring over 150 works borrowed from major British collections, the Louvre, and the Philadelphia Museum of Art, among others—was the first French retrospective devoted to Blake since 1947. This overdue exhibition was expansive and thorough, if not inspirational; it was beautifully installed in the Petit Palais’s well-appointed special exhibition rooms, but...