The coat of arms of Lower Saxony. Also the former ( – 1947) coat of arms of Land Braunschweig. Keep red shade parallel with File:Flag of Germany.svg’s red shade. 

A white Saxon steed (Sachsenross) on a red background.
http://www.niedersachsen.de/live/live.php?navigation_id=6865&amp;article_id=19957&amp;_psmand=1000
Gustav Völker