A system for monitoring the daily activities of a person in a living space, said system including at least one activity detector , and a mobile object intended to be carried by a person to be monitored, and in which system: - the at least one activity detector includes memory and calculation means, and a radio transmission/reception module configured to transmit a detected action signal (S), in the form of a series of radio frames upon detection of any action it monitors; - the mobile object includes calculation means and a radio transmission/reception module configured to receive the signal transmitted by the activity detection device, and to transmit a response (R) including one or more characteristics further associated with the received signal (S); - said system includes a remote information system (SI) including memory and calculation means configured to carry out monitoring of the detected actions assigned to the mobile object of a monitored person; and wherein the monitoring system assigns a detected action to the mobile object according to a signal/response association to a detected action, and the characteristics contained in said response; characterised in that the detected action signal (S) transmitted by the activity detector is in the form of a series of numbered radio frames, and the response (R) of the mobile object includes the number of radio frames received by said mobile object and the reception level of the signal (S) received by said mobile object . - the at least one activity detector includes memory and calculation means, and a radio transmission/reception module configured to transmit a detected action signal (S), in the form of a series of radio frames upon detection of any action it monitors; - the mobile object includes calculation means and a radio transmission/reception module configured to receive the signal transmitted by the activity detection device, and to transmit a response (R) including one or more characteristics further associated with the received signal (S); - said system includes a remote information system (SI) including memory and calculation means configured to carry out monitoring of the detected actions assigned to the mobile object of a monitored person; and wherein the monitoring system assigns a detected action to the mobile object according to a signal/response association to a detected action, and the characteristics contained in said response; characterised in that the detected action signal (S) transmitted by the activity detector is in the form of a series of numbered radio frames, and the response (R) of the mobile object includes the number of radio frames received by said mobile object and the reception level of the signal (S) received by said mobile object . and wherein the monitoring system assigns a detected action to the mobile object according to a signal/response association to a detected action, and the characteristics contained in said response; characterised in that the detected action signal (S) transmitted by the activity detector is in the form of a series of numbered radio frames, and the response (R) of the mobile object includes the number of radio frames received by said mobile object and the reception level of the signal (S) received by said mobile object . <EOS>