Fixing system for recessed luminaire comprising at least - a carrier frame for the luminaire with a cylindrical surface section which is oriented coaxial to a center axle of the carrier frame and which surrounds a recess opening for mounting the luminaire to the carrier frame and with a flat rim section protruding from the cylindrical surface section radially to the outside wherein the flat rim section provides a first contact surface of the fixing system for connecting the fixing system to an outer surface of a ceiling - a clamping unit attached to the carrier frame with a clamping element (flap 9) providing at least one second contact surface of the fixing system for connecting the fixing system to an inner surface of the ceiling the clamping unit being movable form an installation position in which the clamping element (flap 9) is in an upright orientation in such a way that the fixing system can be pushed through a mounting hole of the ceiling to a fixing position in which the clamping element (flap 9) protrudes from the carrier frame with the second contact surface facing the first contact surface in such a way that the ceiling can be wedged between the two contact surfaces (8, 12) wherein the clamping unit comprises at least - a flap as the clamping element wherein the flap provides the second contact surface and at least one control surface which is at least temporarily in contact with a control edge of the carrier frame when moving the flap form the upright installation position to the fixing positior and the flap is designed as a L-shaped flap with a first arm - a nut being fixed to the flap wherein the nut is rotatable with respect to the flap - a screw meshing with the nut in such a way that when rotating the screw the nut linearly travels along a shaft of the screw and the flap is moved from the installation position to the fixing position or vice versa characterized in that the cylindrical surface section provides at least one groove with extends parallel to the center axle with a front side of the groove defining the control edge, and/or that in the installation position the first arm of the flap extends into the groove. - a carrier frame for the luminaire with a cylindrical surface section which is oriented coaxial to a center axle of the carrier frame and which surrounds a recess opening for mounting the luminaire to the carrier frame and with a flat rim section protruding from the cylindrical surface section radially to the outside wherein the flat rim section provides a first contact surface of the fixing system for connecting the fixing system to an outer surface of a ceiling - a clamping unit attached to the carrier frame with a clamping element (flap 9) providing at least one second contact surface of the fixing system for connecting the fixing system to an inner surface of the ceiling - a flap as the clamping element wherein the flap provides the second contact surface and at least one control surface which is at least temporarily in contact with a control edge of the carrier frame when moving the flap form the upright installation position to the fixing positior and the flap is designed as a L-shaped flap with a first arm - a nut being fixed to the flap wherein the nut is rotatable with respect to the flap - a screw meshing with the nut in such a way that when rotating the screw the nut linearly travels along a shaft of the screw and the flap is moved from the installation position to the fixing position or vice versa