Niello is a black mixture of sulfur, copper, silver, and lead, used as an inlay on engraved or etched metal, popular especially in the medieval period and the Renaissance. The process involves filling incised designs on metal surfaces with the niello mixture, which is then fired, causing it to fuse and harden. Once cooled, the surface is polished to reveal the contrasting black niello against the metal, creating a detailed and durable decorative effect.

Niello work was particularly prevalent in Russia, where it was used to decorate silver items such as boxes, jewelry, and religious objects. The depiction of St. Paul's Cathedral on this cigarette case suggests it was likely made for the French market or for someone with an interest in London landmarks. Such cases were popular accessories among the upper classes, showcasing both wealth and refined taste.