Since posting this it has been identified as a Teshner/Collath of Frankfurt gun that takes a special cartridge – as I understand it these guns seem to have been manufactured up to about 1906 and the ammunition was available up to about 1911 – it is now unavailable, making this a Section 58 firearm rather than a Section 2 shotgun. (see end of post and comment)
Here is a German breechloader without any identification. Its a 16 bore hammerless double gun with damasus barrels with an underlever that initially moves the barrels forward away from the breech faces while leaving the extractors behind. Once the underlever has opened 90 degrees, further motion moves the barrel further and causes the bolt that is attached to the underside of the barrel flat to disengage from the slot beneath the breech face, allowing the barrels to fall on a small hingepin at the front of the fore-end. Dropping the barrels disengages the pin that has been holding the extractors in the backward position. The process of opening the gun also cocks it. There is a strange safety catch in the form of a butterfly nut on the top of the breech – when it is aligned fore and aft it is in the safe position and it obstructs the sight line down the barrel – when in the fire position at right angles to the sight line you can see across the middle of it, so it is immediately obvious when you come to shoot that the safety is still on – although it would be difficult to move it from one position to the other while it was anywhere near mounted. The safety is interesting in that it disconnects the triggers rather than blocks them – I haven’t stripped it as it isn’t mine, so I don’t know the details of the action, although I am now tempted. It has the usual continental decoration of raised design against a punched background – possibly etched before punching – rather fine when viewed under the microscope. It has a horn triggerguard and horn facing on the underlever. The gun has sling swivels as was common on continental shotguns, and the chambers appear to be highly tapered for the first 1.5 cm, loosing at least .5mm in diameter – I don’t have a 16 bore snap cap or cartridges to try but I’m sure it won’t fit safely. There are no marks on the gun except a London proof mark and a serial number 6525. The various labels attached to the gun say that it was bought at auction in 1989. There is one label that says Bolath (?) ( p.s. actually Collath) .