A parking brake system for a motor vehicle comprising: - a support structure suitable for being fixed to a frame of said motor vehicle; - a lever, which is coupled to the support structure in a rotary manner according to a first rotation direction starting from a rest position, so as to activate a parking brake of the motor vehicle, and according to a second rotation direction, which is opposite the first rotation direction, so as to loosen or deactivate the parking brake; - a ratchet mechanism, which is operatively coupled to the lever and is configured to lock the rotation of the lever in the second rotation direction in a releasable manner; - an actuator, which is operatively coupled to the ratchet mechanism and can be controlled so as to release the ratchet mechanism in order to permit a rotation in the second rotation direction; - a first transducer, which is coupled to at least one between said lever and said ratchet mechanism and is configured to detect a first quantity indicative of the rotation of the lever in the first rotation direction and to generate a first transduced signal based on the first detected quantity; - a control unit, which is coupled to the first transducer and is configured to: • receive the first transduced signal; and • extract first information associated with the first quantity from the first transduced signal, characterized in that it further comprises a second transducer (T2; T3), which is suitable for being coupled to one between a brake pedal and an accelerator pedal of said motor vehicle and is configured to detect the activation, by a driver of the motor vehicle, of one between the brake pedal and the accelerator pedal, and to generate a second transduced signal (S2; S3) in response to said activation; and in that the control unit is further configured to: • receive the second transduced signal (S2; S3); • compare the first information with a reference value; • control said actuator so as to release the ratchet mechanism when the second transduced signal (S2; S3) is received and the first information reaches a predetermined relation with the reference value. - a support structure suitable for being fixed to a frame of said motor vehicle; - a lever, which is coupled to the support structure in a rotary manner according to a first rotation direction starting from a rest position, so as to activate a parking brake of the motor vehicle, and according to a second rotation direction, which is opposite the first rotation direction, so as to loosen or deactivate the parking brake; - a ratchet mechanism, which is operatively coupled to the lever and is configured to lock the rotation of the lever in the second rotation direction in a releasable manner; - an actuator, which is operatively coupled to the ratchet mechanism and can be controlled so as to release the ratchet mechanism in order to permit a rotation in the second rotation direction; - a first transducer, which is coupled to at least one between said lever and said ratchet mechanism and is configured to detect a first quantity indicative of the rotation of the lever in the first rotation direction and to generate a first transduced signal based on the first detected quantity; - a control unit, which is coupled to the first transducer and is configured to: • receive the first transduced signal; and • extract first information associated with the first quantity from the first transduced signal, characterized in that it further comprises a second transducer (T2; T3), which is suitable for being coupled to one between a brake pedal and an accelerator pedal of said motor vehicle and is configured to detect the activation, by a driver of the motor vehicle, of one between the brake pedal and the accelerator pedal, and to generate a second transduced signal (S2; S3) in response to said activation; and in that the control unit is further configured to: • receive the second transduced signal (S2; S3); • compare the first information with a reference value; • control said actuator so as to release the ratchet mechanism when the second transduced signal (S2; S3) is received and the first information reaches a predetermined relation with the reference value. • receive the first transduced signal; and • extract first information associated with the first quantity from the first transduced signal, characterized in that it further comprises a second transducer (T2; T3), which is suitable for being coupled to one between a brake pedal and an accelerator pedal of said motor vehicle and is configured to detect the activation, by a driver of the motor vehicle, of one between the brake pedal and the accelerator pedal, and to generate a second transduced signal (S2; S3) in response to said activation; and in that the control unit is further configured to: • receive the second transduced signal (S2; S3); • compare the first information with a reference value; • control said actuator so as to release the ratchet mechanism when the second transduced signal (S2; S3) is received and the first information reaches a predetermined relation with the reference value.