He also belonged to the top-level management circle of the Nazi Party and being one of the twenty most intimate co-workers of Hitler in the NSDAP organization moved up the ranks quickly.

[2] From November 1933 until 1945 Fiehler was also a member from electoral constituency 24, Upper Bavaria-Schwabia, of the Nazi Reichstag which existed after the Enabling Act of 1933 and the so-called Gleichschaltung (synchronization).

Despite then First Mayor Karl Scharnagl, who belonged to the conservative Bavarian People's Party (BVP) and who defied the Nazis for eleven days on the top of the old city administration.

The "Book burning" (Bücherverbrennung) on the Königsplatz Square in front of the Staatliche Antikensammlung (Antiquity Collection) on 10 May 1933, the persecution of "non-folkish" (nicht-völkisch) writers, artists and scientists caused an exodus of Munich's intellectual elite.

On 2 August 1935 a memorable conversation took place between Hitler and Karl Fiehler in the course of which Munich received a new epithet: Hauptstadt der Bewegung (Capital of the Movement).

During the 1930s a number of model buildings, prime examples of grandiose Nazi architecture, had been erected by Paul Ludwig Troost, the predecessor of Albert Speer as Hitler's "Court Master Builder", in Munich.

A radical remodelling of Munich was intended, in which Fiehler wanted to illustrate as editor of the pictorial book München baut auf.

The Minister of propaganda, Joseph Goebbels, had already commenced the destruction of Munich's main synagogue in June 1938, just to find out, whether the public's reaction would be shock or indifference.

On 9 November 1938 almost the whole Nazi Party elite convened for a social evening at the invitation of the Lord Mayor Fiehler in the Great Hall of Munich's Old Guildhall.

Johannes Zwanzger, who was appointed head of the "Munich aid office for non-Aryan Christians", formulated a letter of complaint to Lord Mayor Fiehler on behalf of the Bavarian Lutheran Regional Consistory in December 1938, without any success.

Just after their arrival there, the deportees were murdered in a mass shooting by members of the Einsatzgruppen A under the command of SS-Brigadeführer Franz Walter Stahlecker in Fort IX of Kaunas.

Up to February 1945 a total of 42 transports left Munich at irregular intervals: to exterminations in Kaunas, Piaski, (near Lublin), Auschwitz and also at the so-called "Ghetto for old and prominent people", the concentration camp Theresienstadt.

In the early afternoon of 30 April 1945, the first American soldiers led by 27-year-old Lieutenant Wolfgang F. Robinow approached Munich's central square Marienplatz.

On 4 May 1945, four days before the official end of World War II in Europe, the victorious American Forces reinstated Karl Scharnagl as Lord Mayor of the Bavarian capital.

In January 1949 Fiehler, who was married and had three daughters, was sentenced to two years in a labour camp, the confiscation of one fifth of his property and a twelve-year employment ban after Spruchkammerverfahren (proceedings before denazification tribunals).