I think both flags are allowable but my reading of Flag of Germany is that the swastika flag was not internationally recognized at least not by the US see Bremen Incident and as a result was declared the only official flag on 15 September 1935 The 1933 video shows it being used as the Nazi Party NSDAP flag and we can not draw any conclusions from that regarding it s use as the national flag What finally swayed me towards using the flag for the 1933 1935 period is Template Country data Germany which shows the flag variants and when they were used It clearly mentions for the 1933 1935 period and for the 1935 1945 period