The structure of the title compound (4FPMSA), C7H8FNO2S, closely resembles those of N-phenylmethanesulfonamde (PMSA) and other alkyl sulfonanilides. The substitution of either the fluoro, bromo or nitro group at the para position of PMSA does not change the space group, unlike in the case of meta substitutions in PMSA. The geometric parameters in PMSA, 4FPMSA, 4BPMSA and 4NPMSA are similar except for some difference in the angle S2—N5—C6 and some torsional angles. As in other alkyl sulfonanilides, the amide hydrogen sits alone on one side of the plane of the benzene ring, while the whole methanesulfonyl group is on the opposite side of the plane. It is thus available to a receptor molecule during biological activity. The molecules in the title compound are packed into a layer structure in the a-axis direction via N—H⋯O hydrogen bonds [H⋯O = 2.08 (2), N⋯O = 2.911 (6) A and N—H⋯O = 164 (6)°].