My contribution will start with shortly analysing continuity and change in the status of international law under the Weimar Constitution as compared to its forerunner, the ‘Bismarck Constitution’. In the main part of the paper, I will explore the tension between international law and mass democracy. Here, I will keep a focus on the special situation of a newly established order which seeks international trust and a widespread public distrust towards Versailles and international and foreign influences. International treaties of those days, in particular the Treaty of Versailles, and membership in international organisations such as the League of Nations and, in particular, the International Labor Organisation had significant implications for domestic economic and social orders. In that sense, international law, to an unknown extent, reigned into the domestic law of (democratic) states, creating unprecedented tensions between international negotiation processes and domestic audiences.