A filtration system for separating accompanying substances, present in liquid, droplet or mist form, from a gaseous material stream, comprising a housing, in which there is arranged a filter insert, wherein the housing has an inlet and an outlet for said material stream, wherein the filter insert comprises at least two filter layers, wherein one boundary surface of the first filter layer is essentially in parallel with a boundary surface of the second filter layer, wherein at least one boundary surface forms a barrier for said material stream.