This Pauly shotgun is lot #1346 at Morphy's April 2019 auction:

https://auctions.morphyauctions.com/_A__Very_Rare_Pauly_Percussion_Breech_Loading_Shot-LOT464223.aspx

Samuel Johannes Pauli was born outside Bern, Switzerland in 1766, and became an engineer of wide interests. Among them were bridge design, passenger-carrying balloons (he would work seriously on a 15-20 passenger balloon service between London and Paris later in life), and firearms. Only a few years after Forsyth’s invention of fulminate priming, Pauly would become the first to use it in a fully self-contained cartridge. He patented this invention in Paris in 1812, having moved there in 1802 in pursuit of financing for his many grand projects (going then by the name Jean Samuel Pauly).

Pauly’s cartridge was a multi-part affair with a rimmed brass base containing a fulminate powder, connected to a paper or cardboard cartridge body which held a charge of regular gunpowder and the shot or ball to be fired. It was an expensive system, but contained all the necessary elements of a modern cartridge.

Pauly would move to England in 1814 (then taking the name Samuel John Pauly) in pursuit of aviation inventions, although he continued to tinker on his firearms design and filed to additional patent improvements. He died in London in 1821, and his name and work became rather obscure. His former apprentices would carry on his legacy in their own work - Nicolaus Dreyse would produce the needle fire system of Dreyse rifles used by the Prussian military, and Casimir Lefaucheux would create the pinafore system based on Pauly’s designs. Lefaucheux in fact became owner of the company in 1827, and with his son would provide the most direct link between Pauly’s design and the modern metallic cartridge.