It's a German design but built in Denmark to evade ban.

He must be right.
At the time,any kind of military airplane was forbidden.
The first ones appeared when Hitler rised to power.

This is NOT a German aircraft.

The Caspar C.J.14 was a single-seat Danish fighter built and flown in 1925 by the Dansk-Aero Industrie Aktielkabet, of Copenhagen, Denmark.

Top speed with the 300 hp Hispano-Suiza engine shown was approximately 170 mph, and slightly faster with the 380 hp Siddeley Jaguar radial engine fitted later.

Coloring was over-all bright red with black cylinder blocks and Danish markings (Note the vertical white bar on the vertical tail, and the just barely visible horizontal white cross-bar a little over half-way up the vertical white bar. This is the Danish white cross as featured on their national flag).