This contribution presents a new approach to rapid and low-temperature plasma-chemical crystallization of perovskite films. Chlorine-incorporated perovskite (MAPbI(3-x)Cl(x)) films were exposed to diffuse atmospheric hydrogen (H-2) plasma immediately after their deposition. Several types of surface characterization techniques were used to investigate the effect of the H-2 plasma on the surface of the perovskite films. Since the H-2 plasma was generated at a low temperature (<= 70 degrees C), there was no considerable damage to the plasma-treated perovskite films-although the morphology and chemistry changed significantly. H-2 plasma had a range of effects on the surface of the perovskite films: (1) changes in the chemical composition of the perovskite surface without removal of lead; (2) modification of the optoelectrical band structure; (3) crystallization of the perovskite film; and (4) the grain of the surface became highly ordered. The results presented demonstrate that H-2 plasma is a rapid and low-cost method for the manufacture of crystallized perovskite films. The method may be considered a significant step towards low-temperature, annealing-free crystallization of perovskite films.