A MEMS force sensor has: a substrate; a fixed electrode coupled to the substrate; and a mobile electrode suspended above the substrate at the fixed electrode to define a sensing capacitor, the mobile electrode being designed to undergo deformation due to application of a force to be detected. A dielectric material region is set on the fixed electrode and spaced apart by an air gap from the mobile electrode, in resting conditions. The mobile electrode comes to bear upon the dielectric material region upon application of a minimum detectable value of the force, so that a contact surface between the mobile electrode and the dielectric material region increases, in particular in a substantially linear way, as the force increases.