The work indicated in Polish literature as the cartographic basis for the negotiations of Polish issues at the Paris Peace Conference (1919–1920) is Eugeniusz Romer’s ( ). Given the complicated fate of the atlas, the position of its author in the Polish delegation, and the multidisciplinarity and importance of the conference, it is worth considering whether this atlas really played such an important role, or whether this is merely a statement, a repeated assignment of this role, to stave off concealment or lack of knowledge about other cartographic materials developed and used for the same purpose. Therefore, the main aim of this study was to determine the level of use of cartographic documents other than the in lobbying and official negotiations of Polish issues before and during the Paris Peace Conference. The research task was associated with an extensive archival query, which confirmed the fact that dozens of maps survived, mainly manuscripts, which were prepared before and during the conference. It should be concluded that the maps of E. Romer’s atlas constituted one set of many equally important cartographic documents which were used by the negotiators at the Paris Peace Conference.