A chair comprising a base structure (12) bearing a seat (14), a backrest (16) and a writing tablet (38) movable between a first lowered inoperative position and a raised operative position, in which in the first lowered inoperative position the tablet (38) is parallel to a vertical axis and is inclined relative to a vertical plane parallel to the longitudinal axis of the chair, so that two or more chairs of the same type can be approached longitudinally to each other with the tablets of two adjacent chairs partially superposed on each other. The writing tablet (38) is also provided with a second lowered inoperative position in which the tablet is inclined relative to a vertical axis and is inclined relative to said vertical plane parallel to the longitudinal axis of the chair, so that two or more chairs of the same type can also be superposed vertically on each other with the tablets of two adjacent chairs partially superposed on each other.
