Quoting Tom Segev’s The Seventh Million: The Israelis and the Holocaust, pages 32–33:

Ironically, the [Zionist] Revisionists also had fairly wide-ranging links with the Nazis. The Betar youth movement was active in Berlin and several other German cities. About half a year before the Nazis came to power, the movement’s leadership distributed a memorandum to its members that was both commonsensical and cautious.

The Nazis should be treated politely and with reserve, the memorandum instructed. Whenever Betar members were in public, they should remain quiet and refrain from vocal debates and critical comments. Under no circumstances should anyone say anything that could be interpreted as an insult to the German people, to its institutions, or to its prevailing ideology.⁷⁷

The [Third Reich] allowed Betar to continue its activities—meetings, conventions, summer camps, hikes, sports, sailing, and agricultural training. Members were allowed to wear their uniforms, which included brown shirts, and they were allowed to publish mimeographed pamphlets, including Zionist articles in a nationalistic, para-Fascist tone, in the spirit of the times.

The German Betar pamphlets focused on events in Palestine, and their exuberant nationalism targeted the British, the Arabs, and the Zionist left. They contained no references to the political situation in Germany. With this exception, they were similar to nationalist German youth publications, including those published by the [NSDAP]. Jabotinsky decried the influence Hitlerism was having on the members of Betar.⁷⁸

As the Revisionists pushed for a boycott, they could no longer openly support their youth movement in [the Third Reich]. German Betar thus received a new name, Herzlia. The movements activity in [the Third Reich] required, of course, Gestapo approval; in fact, the movement operated under the Gestapo’s protection.

A group of SS men once attacked a Betar summer camp. The head of the movement complained to the Gestapo, and a few days later the secret police announced that the SS men involved had been disciplined. The Gestapo asked Betar what compensation would be appropriate. The movement asked that a recent prohibition forbidding them to wear their brown shirts be lifted; the request was granted.*⁷⁹

Betar was active in Austria as well. Its members continued to meet even after the Anschluss. This required regular contacts with Gestapo representatives and with Adolf Eichmann. Betar leaders sent the German secret police a memorandum offering to organize the emigration of Austrian Jews.

The assumption was that the [German Fascists] and Betar had common interests, just as the [German Fascists] and the Jewish Agency had. The [Third Reich] allowed Betar to open an emigration office and even helped by supplying the emigrants with foreign currency. Most of these emigrants were meant to enter Palestine illegally on boats chartered by Betar.⁸⁰

(Emphasis added.)