This is one of the small 6.35 mm Browning (6.35 x 16) semi-automatic pistols used by the German Police.  This Walther .25 caliber has a six round magazine with a rocker release on the bottom of the grip and a safety lever on the left side of the frame.  This style of small caliber pistol is shown as 10.9 on page 361 of "Dienstwaffen der deutschen Polizei und Gendarmerie" by Horst Friedrich.  

 

These small pistols were referred to as Taschenpistole (pouch/holster pistols) and were used by various police departments such as the Austrian Police who utilized the Steyr Model 1909 and the Bavarian Police who used the Modell 2 and others shown by Friedrich.  This particular Walther is shown to be Bavarian Police property of the City Police of Bamberg by the armor applied markings on the slide.  

 

Now all I need is a small belt or shoulder holster or perhaps a pre-war pouch for my pistol. 

 

Nice pistol.  Rich A. in Pa.