The coat of arms of the Free Hanseatic City of Bremen shows a silver key on a red shield.

The key is the attribute of Simon Petrus, patron saint of the Bremen Cathedral, and it was first represented in the seal of the City of Bremen in 1366, after its liberation from the occupation by Prince-Archbishop Albert II, and later became the main element of the city's coat-of-arms.

Starting in the 16th century, the shield was supported by angels, but from 1568, however, they were replaced by lions.

Napoleon also changed the colors of the coat of arms to the red and gold of his family, this being the only time Bremen used a coat of arms not featuring the historical colors of Bremen, red and white.

After the Napoleonic era, Bremen's previous coat of arms, a silver key on red, were restored.