The building of the Administration of Customs and Excise Duty in Gdańsk, built in the years 1793-1797 at 11 Szafarnia street and destroyed in the last days of WW II, is not so commonly known as David Gilly’s other numerous projects. Only Marlies Lammert included a short description of the building in her book devoted to David Gilly’s activity. Preserved design drawings and office correspondence connected with the construction of the building allow us to follow the whole process of the investment’s realisation from the moment when the project was commissioned down to the final acceptance of the construction investment. The sources show the relationship between the Berlin designer and the Gdańsk constructor Carl Samuel Held who supervised the erection of the building, supervised the work, monitored the remuneration of workers employed at the construction site and the purchase of building materials. Gilly carried out a supervision of the construction once a year; aft er each inspection he made a report concerning expenses and the progress of work. The history of the construction of the building demonstrates that the costs of the investment were reduced to minimum as cheap spare materials were used which frequently came from demolition. Labour costs were also cut. The sources reveal tensions between the mandatory and the Gdańsk workers who did their job following the local tradition and according to their own accounting principles which differed from those the officials from Berlin were accustomed to.