GDR (DDR) flag 10 x 15 cm

With relations deteriorating between the Soviet Union and the United States, the three western Allies met in March 1948 to merge their zones of occupation and allow the formation of a new German nation. This was the Federal Republic of Germany, previously known as West Germany, now simply as Germany. Meanwhile, the eastern Soviet zone became the German Democratic Republic, commonly known as East Germany.

During the preparation of the new constitution for West Germany, discussions regarding its national symbols took place in August 1948 during a meeting at Herrenchiemsee. Although there were objections to the creation of a national flag before reunification with the east, it was decided to proceed. This decision was primarily motivated by the proposed constitution by the eastern SED in November 1946, where black-red-gold were suggested as the colours for a future German republic.

Two variants of Josef Wirmer's 1944 "Resistance" design, created by his brother Ernst. The top flag was proposed by conservative parties as a flag for West Germany (1948).

While there were suggestions for the new flag for West Germany, the final choice was between two designs, both using black-red-gold. The Social Democrats proposed the re-introduction of the old Weimar flag, while the conservative parties such as the CDU/CSU and the German Party proposed a suggestion by Ernst Wirmer, a member of the Parlamentarischer Rat (parliamentary council) and future advisor of chancellor Konrad Adenauer. Wirmer suggested a variant of the 1944 "Resistance" flag designed by his brother and July 20 co-conspirator Josef. The tricolour was ultimately selected, largely to illustrate the continuity between the Weimar Republic and this new German state. With the enactment of the (West) German constitution on 23 May 1949, the black-red-gold tricolour was adopted as the flag for the Federal Republic of Germany.

In 1955, the inhabitants of the French-administered Saar Protectorate voted to join West Germany. Since its establishment as a separate French protectorate in 1947, the Saar had a white Nordic cross on a blue and red background as its flag. To demonstrate the commitment of the Saar to be a part of West Germany, a new flag was selected on 9 July 1956: the black-red-gold tricolour defaced with the new coat of arms, also proposed on this day. This flag came into force on 1 January 1957, upon the establishment of the Saarland as a state of West Germany.

3:5 Flag of the German Democratic Republic (1959–90)While the use of black-red-gold had been suggested in the Soviet zone in 1946, the Second People's Congress in 1948 decided to adopt the old black-white-red tricolour as a national flag for East Germany. This choice was based on the use of these colours by the National Committee for a Free Germany, a German anti-Nazi organisation that operated in the Soviet Union in the last two years of the war. In 1949, following a suggestion from Friedrich Ebert, the black-red-gold tricolour was instead selected as the flag of the German Democratic Republic upon the formation of this state on 7 October 1949. From 1949 to 1959, the flags of both West and East Germany were identical. On 1 October 1959, the East German government changed its flag with the addition of its coat of arms. In West Germany, these changes were seen as a deliberate attempt to divide the two Germanys. Displaying this flag in West Germany and West Berlin – where it became known as the Spalterflagge (divider-flag) – was seen as a breach of the constitution and subsequently banned until the late 1960s.

Flag of the United Team of Germany, as used 1960 to 1968From 1956 to 1964, West and East Germany attended the Winter and Summer Olympic Games as a single team, known as the United Team of Germany. After the East German national flag was changed in 1959, neither country accepted the flag of the other. As a compromise, a new flag was used from 1960 to 1968, featuring the black-red-gold tricolour defaced with white Olympic rings in the red stripe.

reference: http://en.wikipedia.org/wiki/Flag_of_Germany#Divided_Germany