He was the third and final Secretary-General of the Department of Public Information and the Arts [nl], which was established by the civilian regime installed in the Netherlands by Nazi Germany during the occupation.

[1] On 9 February 1943, Hermannus Reydon, who had been made the department's secretary-general following the resignation of Tobie Goedewaagen the previous month, was mortally wounded in an attack by the Dutch resistance.

[6] He also became the president of the Nederlandsche Kultuurkamer (Netherlands Chamber of Culture),[7] an institution tasked with nazifying art by regulating its production and distribution.

[9] De Ranitz left the Hague for the Kultuurkamer's regional office in Groningen, and though work continued, his absence caused the institution and its parent department great difficulty.

[12] Three years later, in mid-December 1948, he was brought before the Special Court of Justice and charged with being a member of the NSB, attempting to subvert Dutch culture, and propagating Nazism.

[13] Ultimately de Ranitz was only sentenced to six years, with the court finding that his position had been forced upon him and that he had not taken measures greatly disadvantageous to Dutch interests.