1932 election she was re-elected. She was not re-elected in the election of March 1933 (in which the NSDAP party obtained an overall majority, and following which the Communist Party members were in any event not permitted to take their seats). The Prussian Landtag held its final session just two months later, in May 1933. Régime change in January 1933 heralded a rapid transition to one-party dictatorship. Work for the communist part became illegal: Friedel Franz pursued her illegal political work. In June 1933 she was arrested because of her political activity. On 15 August 1934 she faced the special "People's Court" and was sentenced to three years in prison, convicted in respect of the standard charge of "preparing to commit high treason" ("Vorbereitung zum Hochverrat"). She served her three-year prison sentence in Jauer before being transferred to the concentration camps at Moringen and then Lichtenburg where she spent a further two years in "protective custody". In 1938 she was released, and during 1938/39 she was working with the Edeka grocery stores co-operative. Around this time she and her husband were divorced. Adolf Franz fled to Moscow where it is thought he died of Typhus in 1942. By 1944 Friedel Franz had moved back to Breslau and was undertaking office work. The 20 July plot to assassinate Adolf Hitler failed in its objective, but succeeded in persuading the government of heightened terrorist risks on the home front. A plan was therefore dusted down which involved arresting a large number of people who had been active as politicians before the Nazi takeover. The official lists were not entirely up to date, many of the names on them belonging to people who had fled abroad or died, but on the night of 22/23 August 1944 approximately 4,000 people who had been politically active before 1933 (and survived inside Nazi Germany since) were arrested. Friedel Franz was among them, in the context of what came to be known as Aktion Gitter: she was transferred to Ravensbrück concentration camp. As a Ravensbrück internee between August 1944 and April 1945, Franz was among those tasked with clerical work for the camp commander. Later she was sent to Genshagen where a sub-camp of the Sachsenhausen concentration camp had been established as part of a programme to try and compensate for the impact on the munitions industry of the country's desperate and intensifying shortage of industrial labour.