Complex sentence: After 1990, a contingent of Jewish refugees came from the former Soviet Union to Germany, hoping to achieve a more developed quality of life, where the Jewish population at the back of the national socialism regime was to be (almost) repented.
Split into simpler sentences: After 1990, as a contingent of Jewish refugees came from the former Soviet Union to Germany. With that the Jews hoped to reach a more developed quality of life, where the Jewish population at the back of the national socialism regime was to be (almost) repented.