Flag of Germany
With the formation of the short-lived Weimar Republic after World War I, the tricolour was adopted as the national flag of Germany. Sixteen years later following World War II, the tricolour was again designated as the flag of both West and East Germany divided states in 1949. The two flags were identical until 1959, when the East German flag was augmented with the coat of arms of East Germany. Since reunification on 3 October 1990, the black-red-gold tricolour has become the flag of a reunified Federal Republic of Germany.
List of German flags
Note: Ottfried Neubecker's proposal of 1919 and those of Josef Wirmer in 1944 and of his brother Ernst in 1948 are clearly modeled on the Nordic Cross flags used in all Nordic countries - the flags of Denmark, Norway, Sweden, Finland and Iceland all having the same horizontal cross, though differing in color. 
The flags of the German overseas colonies were first proposed in 1914, but were never implemented due to the breakout of World War I.