According to The Library of Congress, this artwork is the exhibition poster for Jan Styka’s panoramic painting “The Martyrdom of the Christians in Nero’s Circus” at the Palais de Glace des Champs-Elysee. The LOC offers this transcription of the text from the poster: “Le martyre des chrétiens au palais de Néro par Jan Styka au Palais de Glace des Champs-Elysée“. The advertised panorama was painted in 1897 or 1899 (sources differ) and (according to this Polish website) was lost in Russia during World War I. No images of it turned up in a cursory search.
Image provenance by Bacchus at Erosblog.