System for locating a person by means of telecommunications, said system comprising a smartphone intended to be held by a first person and including first means of communication, the system comprising: - at least one electronic card able to be coupled to the smartphone, and able to be separated from the smartphone so as to be remitted to a second person, with the electronic card including: - second means of wireless communication, able to communicate with the first means of communication; - means of geolocation: - a numerical identification code; - at least one computer application intended to be loaded by the smartphone and able to be programmed in order to memorise the numerical identification code of the electronic card, said computer application being configured to open a communication channel between the smartphone and the electronic card, collect geolocation data supplied by the means of geolocation of the electronic card and make said geolocation data able to be consulted by the smartphone characterised in that the electronic card integrates a rechargeable electric battery, and in that the smartphone comprises a housing carrying: - means of electrical coupling intended to couple the smartphone and the rechargeable electric battery; - means for mechanically coupling the smartphone and the electronic card and in that the system comprises a miniaturised telephone integrating the electronic card, the miniaturised telephone being suitable for being housed in the housing of the smartphone. - at least one electronic card able to be coupled to the smartphone, and able to be separated from the smartphone so as to be remitted to a second person, with the electronic card including: - second means of wireless communication, able to communicate with the first means of communication; - means of geolocation: - a numerical identification code; - at least one computer application intended to be loaded by the smartphone and able to be programmed in order to memorise the numerical identification code of the electronic card, said computer application being configured to open a communication channel between the smartphone and the electronic card, collect geolocation data supplied by the means of geolocation of the electronic card and make said geolocation data able to be consulted by the smartphone characterised in that the electronic card integrates a rechargeable electric battery, and in that the smartphone comprises a housing carrying: - means of electrical coupling intended to couple the smartphone and the rechargeable electric battery; - means for mechanically coupling the smartphone and the electronic card and in that the system comprises a miniaturised telephone integrating the electronic card, the miniaturised telephone being suitable for being housed in the housing of the smartphone. - second means of wireless communication, able to communicate with the first means of communication; - means of geolocation: - a numerical identification code; - at least one computer application intended to be loaded by the smartphone and able to be programmed in order to memorise the numerical identification code of the electronic card, said computer application being configured to open a communication channel between the smartphone and the electronic card, collect geolocation data supplied by the means of geolocation of the electronic card and make said geolocation data able to be consulted by the smartphone characterised in that the electronic card integrates a rechargeable electric battery, and in that the smartphone comprises a housing carrying: - means of electrical coupling intended to couple the smartphone and the rechargeable electric battery; - means for mechanically coupling the smartphone and the electronic card and in that the system comprises a miniaturised telephone integrating the electronic card, the miniaturised telephone being suitable for being housed in the housing of the smartphone. - a numerical identification code; - at least one computer application intended to be loaded by the smartphone and able to be programmed in order to memorise the numerical identification code of the electronic card, said computer application being configured to open a communication channel between the smartphone and the electronic card, collect geolocation data supplied by the means of geolocation of the electronic card and make said geolocation data able to be consulted by the smartphone characterised in that the electronic card integrates a rechargeable electric battery, and in that the smartphone comprises a housing carrying: - means of electrical coupling intended to couple the smartphone and the rechargeable electric battery; - means for mechanically coupling the smartphone and the electronic card and in that the system comprises a miniaturised telephone integrating the electronic card, the miniaturised telephone being suitable for being housed in the housing of the smartphone. - means of electrical coupling intended to couple the smartphone and the rechargeable electric battery; - means for mechanically coupling the smartphone and the electronic card and in that the system comprises a miniaturised telephone integrating the electronic card, the miniaturised telephone being suitable for being housed in the housing of the smartphone.