A method for producing a cold rolled steel sheet having a tensile strength TS of at least 1470 MPa and a total elongation TE of at least 19%, the mechanical properties being measured in the transverse direction relative to the direction of rolling, the method comprising the successive steps of: - annealing at an annealing temperature AT a cold rolled steel sheet made of steel whose chemical composition contains in weight %: 0.34 % ≤ C ≤ 0.40 % 1.50 % ≤ Mn ≤ 2.30 % 1.50 ≤ Si ≤ 2.40% 0.35 % ≤ Cr ≤ 0.45% 0.07 % ≤ Mo ≤ 0.20 % 0.01 % ≤ Al ≤ 0.08 %, and optionally 0% ≤ Nb ≤ 0.05%, the remainder being Fe and unavoidable impurities, Ni, Cu, V, Ti, B, S, P and N being unavoidable impurities with contents of less than 0.05% for Ni, 0.05% for Cu, 0.007% for V, 0.001 % for B, 0.005% for S, 0.02% for P and 0.010% for N, the annealing temperature AT being higher than the Ac3 transformation point of the steel, - quenching the annealed steel sheet by cooling it down to a quenching temperature QT lower than the Ms transformation point of the steel and between 200 °C and 230 °C, during quenching, the annealed steel sheet being cooled down to said quenching temperature at a cooling rate fast enough to avoid ferrite formation upon cooling, in order to obtain a quenched steel sheet having a structure consisting of martensite and austenite, and, - making a partitioning treatment by reheating the quenched steel sheet at a partitioning temperature PT between 350°C and 450°C and maintaining the steel sheet at this temperature during a partitioning time Pt between 25 seconds and 55 seconds, - after partitioning, the steel sheet is galvanized then cooled to the room temperature in order to obtain a coated steel sheet. - annealing at an annealing temperature AT a cold rolled steel sheet made of steel whose chemical composition contains in weight %: 0.34 % ≤ C ≤ 0.40 % 1.50 % ≤ Mn ≤ 2.30 % 1.50 ≤ Si ≤ 2.40% 0.35 % ≤ Cr ≤ 0.45% 0.07 % ≤ Mo ≤ 0.20 % 0.01 % ≤ Al ≤ 0.08 %, and optionally 0% ≤ Nb ≤ 0.05%, the remainder being Fe and unavoidable impurities, Ni, Cu, V, Ti, B, S, P and N being unavoidable impurities with contents of less than 0.05% for Ni, 0.05% for Cu, 0.007% for V, 0.001 % for B, 0.005% for S, 0.02% for P and 0.010% for N, the annealing temperature AT being higher than the Ac3 transformation point of the steel, 0.34 % ≤ C ≤ 0.40 % 1.50 % ≤ Mn ≤ 2.30 % 1.50 ≤ Si ≤ 2.40% 0.35 % ≤ Cr ≤ 0.45% 0.07 % ≤ Mo ≤ 0.20 % 0.01 % ≤ Al ≤ 0.08 %, and optionally 0% ≤ Nb ≤ 0.05%, - quenching the annealed steel sheet by cooling it down to a quenching temperature QT lower than the Ms transformation point of the steel and between 200 °C and 230 °C, during quenching, the annealed steel sheet being cooled down to said quenching temperature at a cooling rate fast enough to avoid ferrite formation upon cooling, in order to obtain a quenched steel sheet having a structure consisting of martensite and austenite, and, - making a partitioning treatment by reheating the quenched steel sheet at a partitioning temperature PT between 350°C and 450°C and maintaining the steel sheet at this temperature during a partitioning time Pt between 25 seconds and 55 seconds, - after partitioning, the steel sheet is galvanized then cooled to the room temperature in order to obtain a coated steel sheet.