Method for estimating a soot load of a particulate filter of a heat engine connected to an exhaust line, comprising: - a step of measuring or estimating an exhaust gas flow rate (Deb_ech), and - a step of selecting a strategy to estimate (Strat _1, Strat_2, Strat_3) loading soots of the particulate filter depending on the flow rate of exhaust gas (Deb_ech) measured or estimated, further comprising: • in the case where the flow rate of exhaust gas (Deb_ech) is less than a minimum threshold calibrated (Qmin), said method includes a step of selecting a strategy for estimating (Strat_1) load ment soot filter with particles based on an open-loop estimator of emission of particles at the output of the heat engine, the estimation method characterized in that: • in the case where the flow rate of the exhaust gases (Deb_ech) is between a calibratable minimum threshold (Qmin) and a calibratable maximum threshold (Qmax), said method comprises a step of selecting an estimation strategy (Strat_2) of the soot loading of the particulate filter based on an open loop estimator of particle emission from the heat engine, a load value soot returned by said estimator being set an update by a value of soot loading estimated from a measurement of a pressure difference (dP) to the terminals of the particulate filter; or • in the case where the flow rate of the exhaust gases (Deb_ech) is greater than a calibratable maximum threshold (Qmax), said method comprises a step of selecting a strategy for estimating (Strat_3) of the soot loading of the filter particles based on an estimator open loop saturated when said estimator returns a value close to a threshold loading critical (S1, S2) corresponding in particular to an overload or a clogging of the filter particles, an exceeding of a critical loading threshold (S1, S2) being detected when a pressure difference (dP) at the terminals of the particulate filter exceeds a threshold value corresponding to this critical loading threshold (S1, S2). - a step of measuring or estimating an exhaust gas flow rate (Deb_ech), and - a step of selecting a strategy to estimate (Strat _1, Strat_2, Strat_3) loading soots of the particulate filter depending on the flow rate of exhaust gas (Deb_ech) measured or estimated, further comprising: • in the case where the flow rate of exhaust gas (Deb_ech) is less than a minimum threshold calibrated (Qmin), said method includes a step of selecting a strategy for estimating (Strat_1) load ment soot filter with particles based on an open-loop estimator of emission of particles at the output of the heat engine, the estimation method characterized in that: • in the case where the flow rate of the exhaust gases (Deb_ech) is between a calibratable minimum threshold (Qmin) and a calibratable maximum threshold (Qmax), said method comprises a step of selecting an estimation strategy (Strat_2) of the soot loading of the particulate filter based on an open loop estimator of particle emission from the heat engine, a load value soot returned by said estimator being set an update by a value of soot loading estimated from a measurement of a pressure difference (dP) to the terminals of the particulate filter; or • in the case where the flow rate of the exhaust gases (Deb_ech) is greater than a calibratable maximum threshold (Qmax), said method comprises a step of selecting a strategy for estimating (Strat_3) of the soot loading of the filter particles based on an estimator open loop saturated when said estimator returns a value close to a threshold loading critical (S1, S2) corresponding in particular to an overload or a clogging of the filter particles, an exceeding of a critical loading threshold (S1, S2) being detected when a pressure difference (dP) at the terminals of the particulate filter exceeds a threshold value corresponding to this critical loading threshold (S1, S2). • in the case where the flow rate of exhaust gas (Deb_ech) is less than a minimum threshold calibrated (Qmin), said method includes a step of selecting a strategy for estimating (Strat_1) load ment soot filter with particles based on an open-loop estimator of emission of particles at the output of the heat engine, the estimation method characterized in that: • in the case where the flow rate of the exhaust gases (Deb_ech) is between a calibratable minimum threshold (Qmin) and a calibratable maximum threshold (Qmax), said method comprises a step of selecting an estimation strategy (Strat_2) of the soot loading of the particulate filter based on an open loop estimator of particle emission from the heat engine, a load value soot returned by said estimator being set an update by a value of soot loading estimated from a measurement of a pressure difference (dP) to the terminals of the particulate filter; or • in the case where the flow rate of the exhaust gases (Deb_ech) is greater than a calibratable maximum threshold (Qmax), said method comprises a step of selecting a strategy for estimating (Strat_3) of the soot loading of the filter particles based on an estimator open loop saturated when said estimator returns a value close to a threshold loading critical (S1, S2) corresponding in particular to an overload or a clogging of the filter particles, an exceeding of a critical loading threshold (S1, S2) being detected when a pressure difference (dP) at the terminals of the particulate filter exceeds a threshold value corresponding to this critical loading threshold (S1, S2).