At the beginning of World War II he was part of German occupation of Poland for a short time from September 1939 to October 1939 as Commander of the Order Police at Army Headquarters 8th.

In September 1944 he was promoted Generalmajor der Polizei, and hence gained in October 1944 the rank of SS-Obersturmbannführer Just prior to Operation Barbarossa, the invasion of the Soviet Union, Franz was appointed commander of Police Regiment South.

The regiment was subordinated to Friedrich Jeckeln, the Higher SS and Police Leader (HSS-PF) for Army Group South in Ukraine.

[2] During August, the regiment murdered Jews in Slavuta, Kowel and other areas, often killing hundreds of victims per battalion per day.

Shortly thereafter, Police Battalion 320 reported the shooting of twenty-two hundred Jews at another location north-east of Kamianets-Podilskyi.

[1] In September, Police Battalion 45 participated in the murder of Jews in Berdichev, cordoning off the execution site and leading the victims to the pits where they were shot by Jeckeln's staff company.

[4] During the massacre at Baby Yar, the same police battalion cordoned off the area, while Sonderkommando 4a and a platoon of the Waffen-SS did the shooting.

As Commander of the Order Police, (Ordnungspolizei; Orpo), he was transferred to Oslo, Norway on 7 February 1945 and remained there until the end of the war on 8 May.