A method for attachment between a mobile radiocommunications network and at least one remote radiocommunications network, the infrastructure of each of the said mobile radiocommunications network and remote radiocommunications network comprising: - a network supervision means (SUPM, SUPD), - an application level (NAPM, NAPD) comprising at least one application (APM, APD), - an authentication and mobility management level (NGAMM, NGAMD), - a radio management level (NGRM, NGRD) comprising at least one base station (BSM, BSD), and - user terminals (TUM, TUD), the method being characterized in that it comprises the following steps: - saving in the mobile network supervision means at least one first inter-network operating model per level to attach to the remote radiocommunications network, - saving in the remote network supervision means at least one second inter-network operating model per level to attach to the mobile radiocommunications upon detection (DECT1, DECT2) of one of the two radiocommunications network by the other radiocommunications network: - configuring (CONF1) each level of the mobile radiocommunications network in accordance with the at least one first inter-network operating model corresponding with the said level, - configuring (CONF2) each level of the remote radiocommunications network in accordance with the at least one second inter-network operating model corresponding with the said level, and - establishing at least one inter-network control channel (Cci) between one element of the mobile radiocommunications network and one element of the remote radiocommunications network and at least one inter-network data channel (Cdi) between one element of the mobile radiocommunications network and one element of the remote radiocommunications network in accordance with the at least one first and at least one second operating models configured per level. - a network supervision means (SUPM, SUPD), - an application level (NAPM, NAPD) comprising at least one application (APM, APD), - an authentication and mobility management level (NGAMM, NGAMD), - a radio management level (NGRM, NGRD) comprising at least one base station (BSM, BSD), and - user terminals (TUM, TUD), - saving in the mobile network supervision means at least one first inter-network operating model per level to attach to the remote radiocommunications network, - saving in the remote network supervision means at least one second inter-network operating model per level to attach to the mobile radiocommunications upon detection (DECT1, DECT2) of one of the two radiocommunications network by the other radiocommunications network: - configuring (CONF1) each level of the mobile radiocommunications network in accordance with the at least one first inter-network operating model corresponding with the said level, - configuring (CONF2) each level of the remote radiocommunications network in accordance with the at least one second inter-network operating model corresponding with the said level, and - establishing at least one inter-network control channel (Cci) between one element of the mobile radiocommunications network and one element of the remote radiocommunications network and at least one inter-network data channel (Cdi) between one element of the mobile radiocommunications network and one element of the remote radiocommunications network in accordance with the at least one first and at least one second operating models configured per level.