An occlusion system implantable in a human or animal body, comprising: - a fluidic circuit comprising: • an inflatable occlusive sleeve containing a variable volume of a fluid, intended to surround at least one portion of a natural conduit to be occluded, • a reservoir with variable volume filled with a fluid, said reservoir comprising a fixed portion and a movable portion, • a fluidic connection between the reservoir and the occlusive sleeve, - an actuator mechanically coupled with the movable portion of the reservoir so as to linearly displace said movable portion relatively to the fixed portion for adjusting the volume of the reservoir, the actuator and the reservoir with variable volume being laid out in a sealed casing containing a gas, said system being characterized in that it further comprises: - a sensor (21, 22) laid out in the casing, mechanically bound to the actuator and/or to the movable portion of the reservoir, laid out so as to measure a traction and/or compressive force in the direction of displacement of the movable portion of the reservoir, said measured force resulting at least from: • the force (F occl) exerted on the movable portion of the reservoir with variable volume related to the pressure in the fluidic circuit, and • the force (F casing) exerted on the movable portion of the reservoir with a variable volume related to the gas pressure in the casing, - a device for measuring the fluid pressure in the fluidic circuit comprising a processing unit configured so as to determine said fluid pressure from a calculation taking into account at least the force measured by said sensor (21, 22), the effective pressure surface area (S eff) of the movable portion of the reservoir, and the force (F casing) exerted on the movable portion of the reservoir with a variable volume related to the gas pressure in the casing. - a fluidic circuit comprising: • an inflatable occlusive sleeve containing a variable volume of a fluid, intended to surround at least one portion of a natural conduit to be occluded, • a reservoir with variable volume filled with a fluid, said reservoir comprising a fixed portion and a movable portion, • a fluidic connection between the reservoir and the occlusive sleeve, • an inflatable occlusive sleeve containing a variable volume of a fluid, intended to surround at least one portion of a natural conduit to be occluded, • a reservoir with variable volume filled with a fluid, said reservoir comprising a fixed portion and a movable portion, • a fluidic connection between the reservoir and the occlusive sleeve, - an actuator mechanically coupled with the movable portion of the reservoir so as to linearly displace said movable portion relatively to the fixed portion for adjusting the volume of the reservoir, - a sensor (21, 22) laid out in the casing, mechanically bound to the actuator and/or to the movable portion of the reservoir, laid out so as to measure a traction and/or compressive force in the direction of displacement of the movable portion of the reservoir, said measured force resulting at least from: • the force (F occl) exerted on the movable portion of the reservoir with variable volume related to the pressure in the fluidic circuit, and • the force (F casing) exerted on the movable portion of the reservoir with a variable volume related to the gas pressure in the casing, • the force (F occl) exerted on the movable portion of the reservoir with variable volume related to the pressure in the fluidic circuit, and • the force (F casing) exerted on the movable portion of the reservoir with a variable volume related to the gas pressure in the casing, - a device for measuring the fluid pressure in the fluidic circuit comprising a processing unit configured so as to determine said fluid pressure from a calculation taking into account at least the force measured by said sensor (21, 22), the effective pressure surface area (S eff) of the movable portion of the reservoir, and the force (F casing) exerted on the movable portion of the reservoir with a variable volume related to the gas pressure in the casing.