A monitoring method implemented by an access point for a network that can maintain an address association table is described. The method can include selecting at least two entries in the address association table, storing at least one predetermined characteristic obtained over a predefined period of time for each inflow and each outflow associated with the selected entries, and comparing, for at least one pair of selected entries, at least one stored characteristic for an inflow associated with one of the entries of the pair with the at least one corresponding stored characteristic for an outflow associated with the other entry of the pair. If, for at least one pair of entries, the comparison step indicates that an inflow associated with one of the entries of the pair transports an application content of the same nature as an outflow associated with the other entry of the pair, a risk of fraud can be detected.