A concealed hinge for a turn-tilt window with a fixed frame and leaf includes of a pair of scissors with a first arm and second arm, that are connected by a central hinge and which are hingeably connected by a first end to a mounting slat that is intended to be mounted on the frame, and have a hinge at a second end for coupling to the leaf. The first arm is connected by its first end to the mounting slat with a fixed frame hinge with a peg fastened to the mounting slat and the second arm is connected by its first end to the mounting slat by a shiftable frame hinge with a peg that is shiftably affixed in a guide slot of the mounting slat, whereby in the closed situation of the scissors, the mounting slat serves as a support for the tilting movement of these scissors.