This is an unknown Imperial German tunic made in the form of a double breasted frock coat. It is heavy blue wool with black cuffs and shoulder straps that are piped in blue. The plain polished (Glatt) gold colored buttons are placed in pairs down the front as well as at the cuffs and back as belt supports. The metal insignia is missing from the stand up collar.
My suspicion is that this coat is either a Police uniform as this blue piping was used by various small municipal police departments known as Kommunalpolizei. It could also be Railway related as the Eisenbahn also used this style of blue coat,
Any thoughts or ideas would be appreciated?