A pairing must be performed between a terminal, referred to as terminal to be paired, and a user account for a service implemented by at least one device connected to a first communication network. The terminal to be paired is connected via a second communication network to a gateway which interconnects the first and second communication networks by performing an address translation by means of a public address routable on the first communication network. A pairing device performs steps: of obtaining (3.2) said public address; of detecting (3.4) an access to said user account, said access being performed from another terminal (1.2), distinct from the terminal to be paired; of obtaining (3.5) the address of said other terminal; of pairing (3.6) the terminal to be paired and said user account if the address of said other terminal coincides with said public address.