System for making shared vehicles available, characterised in that it comprises: - at least one shared vehicle having its own mobile docking chain terminating at one end in a mechanical insert intended to be inserted in a lock, said insert having an electronic chip containing an identifier of the electronic chip and carrying an apparatus comprising a User Interface, a means of reading electronic chips, and an electrical lock for docking the vehicle to at least one fixed point with said mobile docking chain, - at least one portable terminal equipped with a means of communication with a remote server, - a remote server equipped with encryption means and a memory containing codes identifying each vehicle, the reading means reading the identifier of the electronic chip emitted by said electronic chip when the insert containing the electronic chip is inserted in the lock, the on-board device generating information representative of the identifier of the electronic chip contained in the insert inserted in the lock and of an identifier of the vehicle, the introduction of said information at the portable terminal triggering its transmission to the remote server via the communication means, the server generating an authorisation code which is at least a function of the information transmitted and of secret data stored and associated with the vehicle, and transmitting this authorisation code in encrypted form to the portable terminal, a user action entered at the user interface triggering transmission of the authorisation code to the on-board device, reception of this authorisation code unlocking the electric lock, in which the on-board device has a memory containing at least one plurality of identifiers of electronic chips of mooring chain inserts secured to fixed points, the electric lock being configured to lock when the identifier of the electronic chip of the insert inserted in the electric lock corresponds to a said identifier of the electronic chip of an insert of a mooring chain secured to a fixed point, a screen of the user interface then being configured to display an end of rental code that the user transmits to the server, which stores in its memory information specifying that the vehicle is moored at this location and authorises the rental of a vehicle from this location, and in which the on-board device is configured so as not to lock the electrical lock on the inserted insert when the identifier of the electronic chip corresponds neither to a securing chain secured to a fixed location, nor to the mobile securing chain of the vehicle, the on-board device being configured, on insertion of such an insert whose identifier of the electronic chip is not recognised by the on-board device, so as to trigger the display of a message informing that locking is not possible. - at least one shared vehicle having its own mobile docking chain terminating at one end in a mechanical insert intended to be inserted in a lock, said insert having an electronic chip containing an identifier of the electronic chip and carrying an apparatus comprising a User Interface, a means of reading electronic chips, and an electrical lock for docking the vehicle to at least one fixed point with said mobile docking chain, - at least one portable terminal equipped with a means of communication with a remote server, - a remote server equipped with encryption means and a memory containing codes identifying each vehicle, the reading means reading the identifier of the electronic chip emitted by said electronic chip when the insert containing the electronic chip is inserted in the lock, the on-board device generating information representative of the identifier of the electronic chip contained in the insert inserted in the lock and of an identifier of the vehicle, the introduction of said information at the portable terminal triggering its transmission to the remote server via the communication means, the server generating an authorisation code which is at least a function of the information transmitted and of secret data stored and associated with the vehicle, and transmitting this authorisation code in encrypted form to the portable terminal, a user action entered at the user interface triggering transmission of the authorisation code to the on-board device, reception of this authorisation code unlocking the electric lock, in which the on-board device has a memory containing at least one plurality of identifiers of electronic chips of mooring chain inserts secured to fixed points, the electric lock being configured to lock when the identifier of the electronic chip of the insert inserted in the electric lock corresponds to a said identifier of the electronic chip of an insert of a mooring chain secured to a fixed point, a screen of the user interface then being configured to display an end of rental code that the user transmits to the server, which stores in its memory information specifying that the vehicle is moored at this location and authorises the rental of a vehicle from this location, and in which the on-board device is configured so as not to lock the electrical lock on the inserted insert when the identifier of the electronic chip corresponds neither to a securing chain secured to a fixed location, nor to the mobile securing chain of the vehicle, the on-board device being configured, on insertion of such an insert whose identifier of the electronic chip is not recognised by the on-board device, so as to trigger the display of a message informing that locking is not possible.