Heeresgruppe E
Following the German invasion of Greece in April 1941 and the occupation of the country by Nazi Germany, Italy, and Bulgaria, in 1942 Zamboni was appointed Consul General in Thessaloniki, the second largest city in Greece, which was occupied by Germany. The appointment was a promotion, as Thessaloniki was the headquarters of Army Group E that consisted of all the Wehrmacht forces in the Balkans, putting Zamboni in charge of relations with Field Marshal Alexander Löhr who served as the military governor of the areas occupied by Army Group E. The American historian Jonathan Steinberg called Zamboni a "tiny, lively and combative" man who spoke his Italian with a strong Romagna accent.