There are 3 possibilities for your gun. The 7.65 caliber (32) is a semi auto pistol with a 3.65" barrel. The slide is marked Rheinmetall ABT. Sommerda. The finish is blued and original grips were walnut. The values on this gun are:
excellent-$350, very good-$225, good-$175, fair-$125, poor-$90.
There is a 9mm version of this gun that is marked the same on the slide. The gun is too rare to price and it should go to a certified appraiser.
The other is a 9mm with a 5" barrel and an 8 shot magazine. The slide is marked Rheinische Metallwaaren Und Maschinefabrik, Sommerda. It is blued and had hard rubber grips. It was manufactured before 1916 in small numbers. Values are:
excellent-$4500, very good-$3750, good-$2500, fair-$1500, poor-$750.
Ivory grips can add $100 to $150 to the value.
There are only a few states that require permits for handguns. Among them are NY, NJ, and Ill. You can go to www.nra-ila.org and click on gun laws at the top of the page. Then click on your state and it will give you the laws for the state.
I hope this helps you,