This is the Dewoitine D.520 addon for the game FlightGear
The Dewoitine D.520 was a French fighter aircraft. The Dewoitine D.520 came close to being a match for the latest German types, such as the Messerschmitt Bf 109.
To install this aircraft, download the .zip archive to your local hard drive, and extract them into your Aircraft folder. For windows users, this will be located in C:\Program Files\FlightGear\data\Aircraft.