Microelectromechanical system (MEMS) comprising: an active part (5) comprising an electromechanical device (28), at least one base (6) for fastening said microsystem on a support (8), at least one fastener (21, 21') fastening said active part (5) to said at least one base (6) and allowing a displacement of said active part (5) relatively to said at least one base (6) along an axis (Z) more or less perpendicular to the plane of said support (8) when said microsystem is fastened onto said support (8), bumper elements (27, 27', 37') for limiting the amplitude of the displacements of said active part (5) relatively to said at least one base (6) along said perpendicular axis (Z). The active part (5) being capable of moving relatively to the base (6) to which it is fastened, it is isolated from any mechanical constraint that could be sustained by the base (6), in particular torsion or flexion due to it being fastened onto a support (8). On the other hand, since the movements of the active part (5) are limited by the bumper elements (27, 37, 27', 37'), it can be guaranteed thanks to the invention that the fastener or fasteners (21, 21') will not be stretched beyond their elasticity range, thus avoiding their irreversible deformation and/or their rupture.