This boom was also reflected in the circulation of the newspaper which reached its maximum at 15,000 copies in the beginning of the 1930s. The reading groups which were formed in many German cities and even in South America showed the impact of the paper. Outside of these groups, the paper attracted attention by lawsuits with the Ministry of the Reichswehr about the anti-militaristic reporting done by the paper's journalists. The climax of these conflicts was the so-called Weltbühne-Prozess in which Ossietzky and the journalist Walter Kreiser were sentenced to 18 months in prison.