This one is in its original 9mm Largo, also known as 9x23mm Bergmann-Bayard.
It is similar in size and heft to the familiar M1911A1 and despite appearances the grip is comfortable and points easily.
Hilariously, it's so similar that you can use a US M1916 holster.
It's very similar to a Browning blow-back gun inside.
Takedown for cleaning is similar to Brownings too.
The safety will engage a notch in the slide that lets the groves in the barrel be rotated into a recess in the slide. Then the whole barrel, recoil spring and slide just slide right off the front.
If, for some reason you need to get at the recoil spring, it's a little more involved.
There's a strong temptation to think that the knurled cap on the nose is stuck and you need to apply more force... be sure to read the instructions at that link!
The cap is keyed, you rotate it to align with grooves in the slide and it will fire out the front under spring pressure if you let it. The reason you cannot freely turn it is there are lugs on the barrel bushing that block the grooves in the slide.
|Nose cap and bushing as they normally sit.|
|Nose cap and bushing aligned for disassembly.|
|L->R 9x19mm Parabellum, 9mm Largo, .38 Super|
He even lucked out and there's a local shop with almost a case of Santa Barbara 124gr ammunition for it.