A native of Mülheim in the Ruhr, in the early years of Nazi Germany Fünten was employed in the Jewish section of the Reich Security Main Office, under the command of Adolf Eichmann. After the occupation of the Netherlands by German troops, Fünten became head of the Central Office for Jewish Emigration in Amsterdam. In this capacity, he was subordinate to the commander of the "Sicherheitspolizei" and the SD in The Hague. As head of the Central Office for Jewish Emigration, he organized the registration and arrest of Dutch Jews. Those arrested were taken to the Westerbork transit camp and deported to concentration and extermination camps in German-occupied Poland. Among those deported were sick and insane Jews from Amsterdam and Apeldoorn. Fünten threatened Jews who had married non-Jews with deportation, in order to force their sterilization. He held the rank of "Hauptsturmführer" in the SS in 1941.