[1] In 1911/12, he studied painting and architecture at the Technical University of Munich and visited art collections in Germany and Italy.
He travelled to Moscow and made acquaintance with the Cubofuturists there such as Alexei Jelissejewitsch Krutschonych, Wladimir Majakowski and Dawid Burljuk, as well as with Russian avant-gardists Mikhail Larionov and Natalia Goncharova.
From 1920, he lectured at the Tartu School of Art, campaigned for Jewish cultural autonomy in Estonia, which was realized in 1925, and was an active member of Pallas, the Estonian Society of Artists and Writers.
In July 1941, the Genss family had to leave Tallinn to escape the persecution of Estonian Jews by the German occupying forces.
In November 1944, Rosenberg reported 61 boxes of the Genss collection in the barracks in Pless, which were named among the most important for removal to Minsk.
Judaica formed a focal point of the collection, which mainly consisted of items from France, Russia and Germany.
He had several owner's stamps; he ordered four used bookplates, each in an edition of 2,000, so that the book's inclusion in the library could later be traced on the basis of these.
The graphics collection consisted of almost 3,000 sheets, including works by Marc Chagall, Lyonel Feininger, Paul Klee, Léon Bakst, El Lissitzky and Konstantin Korovin.
On his travels, Genss visited synagogues and Jewish museums, acquired catalogs and specialist literature.
His Judaica collection continued to grow, and in 1938/39 he organized a travelling exhibition that was presented in Tartu, Tallinn and Riga: "I wanted to prove the existence of modern Jewish art," he later wrote in his memoirs.
Artists from Paris, Warsaw, Vilnius, even Israel and the Soviet Union sent him prints and illustrations at his request.
An exhibition catalog was published - in Estonian and in Yiddish, the common idiom among the Jews of Eastern Europe at the time.
Among them was a particularly valuable piece: a scroll with the Song of Solomon, written in Hebrew by Genss himself in the early 1930s and illustrated by his friend, the Estonian artist Ado Vabbe.
Polish artists were the most fully represented, contributing eleven prints from Paris, Warsaw, Vilnius and the USA.
Among the renowned masters, Chagall, Israëls and Liebermann were exhibited, as well as ornaments by Natan Altman.
[13] In 1941, the collection was confiscated by the "Einsatzstab Reichsleiter Rosenberg", which systematically plundered Jewish cultural treasures in Eastern Europe.
His daughter Inna Gens recalls in an interview with Deutsche Welle: "Paul Ariste had worked in the Rosenberg task force.
According to ERR reports (#61432592 page: 208) quote: "...mainly on the basis of the information provided by the university lecturer Dr. Arriste, the following apparently definitive statements were made about the current whereabouts of the library of the Jew Genss:..."[15] In 2012, fragments of the Julius Genss collection were shown as part of an exhibition "Jews 45/90" (July 2012 - January 2013) at the Jewish Museum Munich.