In order to provide a filter system for separating off contaminants from a stream of untreated gas that contains contaminants that is of simple construction and is operable efficiently, it is proposed that the filter system should include the following: a base construction through which the stream of untreated gas is guidable and which includes at least one filter module receptacle for receiving at least one filter module, and at least one filter module which is selectively arrangeable on and/or in the at least one filter module receptacle and/or removable therefrom, wherein the at least one filter module includes a plurality of filter element receptacles for receiving a plurality of mutually independent filter elements.