1. A method for opening a session of a first machine using session checking means for a machine set, the machine set comprising at least the first machine and a second machine, in which the second machine comprises security means, the method comprising: receiving, by the session checking means, a request to open the session on the first machine, the request comprising at least one item of identification information of a user; verifying, by the session checking means, that the at least one item of identification information of the user is associated with an item of identification data of the second machine in a repository; and checking, by the session checking means, whether the user has the right to open the session on the first machine, wherein, in response to the verification and check results being positive, sending, by the session checking means, to the security means of the second machine a session status modification request for locking an existing session on the second machine that was previously opened by the user, in response to the session status of the second machine being modified, sending, by the session checking means, to the first machine a request to authorize opening of the session on the first machine, storing, by the session checking means, the at least one identification information item for the user that is associated with an item of identifying data of the first machine in the repository, and sending, by the first machine to the session checking means, a configuration request that includes a type of the session status modification request, the type of the session status modification request corresponding to the locking of the existing session.