Siegfried Engelbert Martin Rädel (7 March 1893 – 10 May 1943) was a German politician, a member of the Communist Party of Germany (KPD) and a resistance fighter against the Nazi régime.
In France, where he found himself after being expelled from Switzerland, the Secretariat of the KPD Central Committee, which at that time was based in Paris, transferred to Rädel the leadership of the Communist emigrant organization.
At the KPD's "Bern Conference" in Draveil near Paris, he was chosen to be one of the 17 members of the Central Committee.
However, with the German-Soviet non-aggression pact came the arrest and detention in 1940 of every German Communist émigré in France, including Rädel, who was delivered to Le Vernet concentration camp.
In a high treason trial, he was sentenced by the Volksgerichtshof to death on 25 February 1943, shortly before his 50th birthday, and executed on 10 May 1943 in the infamous "murder garage" at Brandenburg Prison.