Method for selecting a modulation to be used in a transmission of a frame between a first and a second network device (2, 3), said transmission using a power-line communication protocol, the first and second network devices (2, 3) regularly implementing an adaptive tone mapping procedure making it possible to determine, for each tone in a set of tones which are defined by said protocol in a frequency band used for said transmission, whether said tone offers a sufficient reliability according to a predetermined criterion for allowing transmissions of frames, and to determine a preferred modulation depending on said tones offering a sufficient reliability, each transmission of a frame applying a robust transmission procedure making it possible, in the case of failure of said transmission, to reiterate said transmission up to a maximum number of successive transmissions, characterized in that: the method comprises the following steps for each transmission of one and the same frame in the context of the robust transmission procedure: determining a number of performed transmissions for said frame; obtaining a list of modulations, comprising at least two different modulations, which is suitable for the preferred modulation, said list being ordered such that a first modulation preceding a second modulation in the list ensures a robustness against transmission errors which is smaller than or equal to the second modulation, each modulation from said list ensuring a robustness against the transmission errors which is at least equal to the robustness of the preferred modulation; and selecting a modulation from said list having a rank equal to said number of transmissions; and in that, when, following a successful transmission (336, 337, 338) of a frame using a selected modulation, if the selected modulation is different from the modulation from said list ensuring a minimum robustness, said list is modified such that each modulation of lower rank than the minimum rank of the selected modulation in said list is replaced by a modulation from the set of modulations which are defined by said protocol ensuring a robustness against the transmission errors which is at least equal to the robustness of the preferred modulation and at most equal to the robustness of the selected modulation. determining a number of performed transmissions for said frame; obtaining a list of modulations, comprising at least two different modulations, which is suitable for the preferred modulation, said list being ordered such that a first modulation preceding a second modulation in the list ensures a robustness against transmission errors which is smaller than or equal to the second modulation, each modulation from said list ensuring a robustness against the transmission errors which is at least equal to the robustness of the preferred modulation; and selecting a modulation from said list having a rank equal to said number of transmissions; and in that, when, following a successful transmission (336, 337, 338) of a frame using a selected modulation, if the selected modulation is different from the modulation from said list ensuring a minimum robustness, said list is modified such that each modulation of lower rank than the minimum rank of the selected modulation in said list is replaced by a modulation from the set of modulations which are defined by said protocol ensuring a robustness against the transmission errors which is at least equal to the robustness of the preferred modulation and at most equal to the robustness of the selected modulation.