According to the process for monitoring the consumptions of a plurality of franking machines through a public communication network, at least one franking machine not being connected to this network, a link is firstly established with a management server, through the public network, by means of at least one supervision terminal independent of the off-line franking machine, in accordance with a determined protocol of communication, and data is then exchanged between the terminal and the server during which the user inputs at the supervision terminal a current invoicing index relative to the off-line franking machine and receives in return a code of authorization to frank in order to validate the subsequent frankings of the off-line franking machine.