A method for producing a coated steel sheet having a tensile strength TS of at least 1100 MPa, a total elongation TE according to ISO standard 6892-1 of at least 12%, the product TSxTE of the tensile strength by the total elongation being at least 14200 MPa%, and a hole expansion ratio HER according to ISO standard 16630:2009 of at least 25%, wherein the method comprises the following successive steps: - providing a cold-rolled steel sheet, the chemical composition of the steel containing in weight %: 0.15 ⁢ % ≤ C ≤ 0.23 ⁢ % , 2.0 % ≤ Mn ≤ 2.7 ⁢ % , with C + Mn / 10 ≥ 0.420 ⁢ % , 0 ≤ Cr ≤ 0.40 ⁢ % , with Mn + Cr ≥ 2.25 ⁢ % , 0.2 ⁢ % ≤ Si ≤ 1.6 ⁢ % 0.02 ⁢ % ≤ Al ≤ 1.2 ⁢ % , with 1.0 % ≤ Si + Al ≤ 2.2 ⁢ % , 0 ≤ Nb ≤ 0.035 % , 0 ≤ Mo ≤ 0.1 ⁢ % , the remainder being Fe and unavoidable impurities, - annealing the steel sheet at an annealing temperature T A so as to obtain a structure comprising at least 65% of austenite and at most 35% of intercritical ferrite, - quenching the sheet from a temperature of at least 600°C at a cooling rate comprised between 20°C/s and 50°C/s down to a quenching temperature QT between 200°C and 270°C, - heating the sheet up to a partitioning temperature PT comprised between 400°C and 480°C and maintaining the sheet at this partitioning temperature PT for a partitioning time Pt comprised between 50s and 250s, - hot-dip coating the sheet at a temperature less than 515°C, - cooling the coated sheet down to the room temperature, the steel sheet having a microstructure consisting of, in surface fraction : - between 3 % and 15% of retained austenite, - at least 30% of tempered martensite, - at most 5% of fresh martensite, - at most 35% of bainite, the sum of the surface fractions of tempered martensite, fresh martensite and bainite being comprised between 55% and 92%, - between 5% and 35% of ferrite. - providing a cold-rolled steel sheet, the chemical composition of the steel containing in weight %: 0.15 ⁢ % ≤ C ≤ 0.23 ⁢ % , 2.0 % ≤ Mn ≤ 2.7 ⁢ % , with C + Mn / 10 ≥ 0.420 ⁢ % , 0 ≤ Cr ≤ 0.40 ⁢ % , with Mn + Cr ≥ 2.25 ⁢ % , 0.2 ⁢ % ≤ Si ≤ 1.6 ⁢ % 0.02 ⁢ % ≤ Al ≤ 1.2 ⁢ % , with 1.0 % ≤ Si + Al ≤ 2.2 ⁢ % , 0 ≤ Nb ≤ 0.035 % , 0 ≤ Mo ≤ 0.1 ⁢ % , the remainder being Fe and unavoidable impurities, - annealing the steel sheet at an annealing temperature T A so as to obtain a structure comprising at least 65% of austenite and at most 35% of intercritical ferrite, - quenching the sheet from a temperature of at least 600°C at a cooling rate comprised between 20°C/s and 50°C/s down to a quenching temperature QT between 200°C and 270°C, - heating the sheet up to a partitioning temperature PT comprised between 400°C and 480°C and maintaining the sheet at this partitioning temperature PT for a partitioning time Pt comprised between 50s and 250s, - hot-dip coating the sheet at a temperature less than 515°C, - cooling the coated sheet down to the room temperature, - between 3 % and 15% of retained austenite, - at least 30% of tempered martensite, - at most 5% of fresh martensite, - at most 35% of bainite, the sum of the surface fractions of tempered martensite, fresh martensite and bainite being comprised between 55% and 92%, - between 5% and 35% of ferrite. <EOS>