The shot noise suppression in a sample containing a layer of self-assembled InAs quantum dots has been investigated experimentally and theoretically. The observation of a non-monotonic dependence of the Fano factor on the bias voltage in a regime where only few quantum dot ground states contribute to the tunneling current is analyzed by a master equation model. Under the assumption of tunneling through states without Coulomb interaction this behaviour can be qualitatively reproduced by an analytical expression.