A large-surface luminaire for recessed installation in ceilings that can be manufactured in any size, shape or power variant in order to perfectly suit any room. Painted steel sheet housing. A diffuser made of light-permeable, evenly illuminated, non-inflammable, non-toxic, flexible, deformation- and moisture-resistant PVC thermoelastic foil. The foil has glare-reducing properties that make the luminaire suitable for use in offices. Colored patterns can be printed on the foil and an acoustic version is also available. The diffuser is opened using magnets or a system of bolts. The luminaire is equipped with a light source and separate lighting control equipment that cannot be replaced by the user.