unknown brass plate with A.H. + eagle + Reichskanzlei

[screensize]

the letters say:

in memory of the finalisation of the Reichskanzlei.

Risen from March 1938 until today.

Dedicated to the staff.

Berlin 9. January 1940

Measurements:
Width: 13 cm (5.1 inches)
Height: 25 cm (9.8 inches)
Weight: 1.3 kilo (2.8 lbs)

Has anyone ever seen something like this ?

Thanks,
Chris