After the founding of Germany's Customs Union in 1834 of which Nassau also became a member, Frankfurt was the only city that was not part of Prussian Customs Union, in contrast to the surrounding area.
Pärast Saksamaa Tolliliidu asutamist aastal 1834, mille liige oli ka Nassau, oli Frankfurt ainus linn, mis ei olnud osa Preisi Tolliliidust, erinevalt ümberkaudsetest aladest.