The present invention refers to a floor cleaning machine comprising a brush adapted to scrub the floor with a cleaning, i.e. detergent, liquid in view of removing soil and dirt therefrom, and a wiping device adapted to scrape the floor in order to remove the dirty cleaning liquid therefrom; the wiping device comprises a front flap and a rear flap adapted to elastically and slidably engage the floor so as to define a suction chamber therebetween, wherein the suction chamber is fluidly connected to a suction device, and wherein the front flap is provided with a plurality of indentations of a reduced cross-sectional size to convey the dirty cleaning liquid into the suction chamber; at least a portion of the front flap is provided in the form of a tab that is associated to the same front flap via a rupture edge, wherein such tab is adapted to be removed so as to form a breach or passageway having a broader cross-sectional size in the front flap in order to reduce the speed of the air entering the suction chamber and, as a result, the related suction noise.