This looks like a nice bargain! Buy-it-now price is $699.99, and the horn is in very nice condition. Case is included. This was made in the 1950's and would have the full, rich Besson sound. You're just missing a 4th valve - if you don't need it, this is a heckuva buy!
This could go quickly!
https://www.ebay.com/itm/Besson-Euph...l/153715209858