Geno,

Adolphe Jansen, rue de la Madeleine 27, Brussels 1859 to 1884. He was Gunmaker to the King under Leopold I and II.

He developed pistols and carbines. He worked on modifications of the Lefaucheux and on a type of choke system.

There is more about him here:
http://www.littlegun.be/arme%20belge/art...dolphe%20gb.htm

Fascinating cape gun.

Pete