This is postmarked in 1939 with a special cancelation from Braunau for Hitlers 50th Birthday 1889-1939.
The Hitler Reich stamp is pre-printed onto the postcard.
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This is from a series that was issued on 13 April 1939 to commemorate Hitler's 50th birthday. (I think there were five in the series)
The stamp design is like the 1938 Party Rally stamp except that it is a different color.