A filter medium for removing particles from a fluid flow has a pre-filter layer and a fine-filter layer joined to each other in the flow direction. A first supporting layer is attached to the unfiltered side of the pre-filter layer and a second supporting layer is attached to the filtered side of the fine-filter layer in order to absorb the longitudinal and transverse forces in the event of tensile loading. The traverse force absorbing layer has a greater bending stiffness in a traverse direction while the longitudinal force absorbing layer has a greater bending stiffness in a longitudinal direction.