After World War I, in the Upper Silesia plebiscite held in March 1921, 79.5% of the citizens of Guttentag came out in favour of a continuance in Germany, and while most parts of the Lubliniec district were reintegrated with the re-established Polish Republic, Dobrodzień, as "Guttentag", remained on the German side, within the Prussian Province of Upper Silesia and ended up very close to the new German–Polish border. In May 1921 it was still captured by Polish insurgents during the Third Silesian Uprising, however it remained part of Germany after 1922. Several Polish organizations and enterprises operated in the town in the interbellum, including the Union of Poles in Germany, a Polish scout troop and the Polish "Bank Ludowy" ("People's Bank"). Polish activists were persecuted since 1937. In the months before the outbreak of World War II, in 1939, the houses of Polish activists and Polish institutions and enterprises were the target of numerous attacks, anonymous threatening letters were sent to Poles, while the police refused protection. After the invasion of Poland, which started World War II, the assets of the Polish bank were confiscated by the German state. Jews, most of whom supported Germany against Poland in the 1921 plebiscite, were also persecuted by the Germans in the 1930s, resulting in their emigration to the west. The synagogue was dismantled by the Germans.