Requests for information had also been made to the LHM. At the latest with the introduction of a digital inventory database in 2010 and an offensive new focus on this topic, provenance research was established in its collection. The temporary establishment of a dedicated provenance research unit on the initiative of the then director Dr. Renate Goldmann, which was funded by the German Center for the Loss of Cultural Property from 2015 to 2018, made it possible to investigate the provenance of more than two thousand works and also to clarify the history of the collection holdings before World War II.
The aim of the project was to systematically research the provenance of paintings, pastels, watercolors, sculptures, hand drawings, and prints acquired between 1933 and 1960 and to document them as completely as possible. If the origin of the works was incriminated in the provenance chain, contact was made with possible heirs in order to negotiate a fair and equitable solution with them. Some cases were brought to a successful conclusion. Other works suspected in the provenance chain were entered into the international Lost Art database. They had been purchased from art dealers known to have sometimes traded in Nazi-confiscated cultural property, while no evidence could be provided for their unlawful acquisition.
Of particular importance for the art collections of the LHM are the restitution and subsequent acquisition of the painting "Ostsee/Schiffe am Strand" (Baltic Sea/Ships on the Beach) by Karl Schmidt-Rottluff from the former Berlin art collection of Hugo Benario and the painting "Tiere/Bild mit Tieren" (Animals/Picture with Animals) by the Rhenish Expressionist Heinrich Campendonk from the estate of the Erfurt industrialist and collector couple Alfred and Thekla Hess. In both cases, the loss of the artworks due to persecution was acknowledged. It was possible to reach an agreement with the respective descendants for a purchase by the city of Düren as the responsible body of the LHM. This was generously supported by the Federal Government Commissioner for Culture and the Media, the Cultural Foundation of the Federal States, the Ernst von Siemens Art Foundation and the Ministry of Culture and Science of the State of North Rhine-Westphalia. In this way, it was possible to ensure that these two art-historically important Expressionist paintings would remain in the art collections of the LHM.