Method for synchronizing a data stream transmitted on a communications network, the data stream being transmitted from an emitter device to a receiver device in the form of transmission packets including a payload part of predefined size, a transmission packet being filled up with a padding synchronization symbol if an amount of applications data to be transmitted in said transmission packet is below the predefined size of said payload part of said transmission packet, said method performs the following steps in the receiver: - obtaining an indication of a recurrence of filling of said transmission packets with padding synchronization symbols; - upon detection, at a position in said data stream, of a data loss symbol representative of a lost data in a given transmission packet, deciding whether the lost data corresponds to an applications data or a padding synchronization symbol, as a function of a position of said given transmission packets in said recurrence; and - marking that said data stream contains, at said position where the data loss symbol is detected, an erroneous applications data, if the result of said deciding step is that said lost data corresponds to an applications data; or - replacing said data loss symbol by a padding synchronization symbol, if the result of said deciding step is that said lost data corresponds to a padding synchronization symbol; - counting a number of padding synchronization symbols received, including data loss symbols replaced by padding synchronization symbols; - receiving a piece of information from the sender device indicating a number of padding synchronization symbols sent; - if said number of padding synchronization symbols sent is greater than said number of padding synchronization symbols received, replacing an applications data by a padding synchronization symbol in said data stream. - obtaining an indication of a recurrence of filling of said transmission packets with padding synchronization symbols; - upon detection, at a position in said data stream, of a data loss symbol representative of a lost data in a given transmission packet, deciding whether the lost data corresponds to an applications data or a padding synchronization symbol, as a function of a position of said given transmission packets in said recurrence; and - marking that said data stream contains, at said position where the data loss symbol is detected, an erroneous applications data, if the result of said deciding step is that said lost data corresponds to an applications data; or - replacing said data loss symbol by a padding synchronization symbol, if the result of said deciding step is that said lost data corresponds to a padding synchronization symbol; - counting a number of padding synchronization symbols received, including data loss symbols replaced by padding synchronization symbols; - receiving a piece of information from the sender device indicating a number of padding synchronization symbols sent; - if said number of padding synchronization symbols sent is greater than said number of padding synchronization symbols received, replacing an applications data by a padding synchronization symbol in said data stream. <EOS>