The Affair at the Semiramis Hotel is a 1917 detective novella by the British writer A. E. W. Mason featuring his character Inspector Hanaud. Mason had originally written many of the plot elements for an abortive silent film, to be called The Carnival Ball. The novella appeared between Mason’s first full-length Hanaud novel, At the Villa Rose (1910), and his second, The House of the Arrow (1934).