After attending the Honnefer elementary school and the Kalkuhl private school in Oberkassel, he worked from 1901 to 1902 as a trainee timber merchant in Munich and Regen (among others at Gebr. Freundlich), where he met the painter Albert Weisgerber. In 1908 he began studying at the Munich School of Applied Arts with Maximilian Dasio. In the same year, Broel studied in the painting class of Hermann Groeber at the Munich Academy and became a member of the Freie Gruppe Düsseldorf with Albert Welti and Heinrich Reifferscheid, among others. After his father's death on March 31, 1908, Broel took over his father's business, but returned to Munich in 1909, where he also continued his studies. In 1910 he had the first exhibition with Karl Haider, Edmund Steppes and Heinrich Reifferscheid in Wiesbaden and Dresden. As a member of the Munich artists' cooperative, he took part in the Munich art exhibition several times from 1910. On June 6, 1911, he married Alexandra (Schura) Korsakoff, a Russian artist. In the years that followed, Broel lived in Schleißheim and Dachau, then in Munich-Schwabing from October 1914, initially on Bismarckstrasse and later on Agnesstrasse. In 1914, during the First World War, Broel was an officer in the List Regiment in Flanders. Some drawings with this time reference were published in "Simplicissimus" and in the "Meggendorfer Blatter". In 1915 the Spring Symphony cycle was published by Bruckmann in Munich.