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 100°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, at a cooling speed higher than 10°C/s, the steel sheet having a microstructure consisting of, in surface fraction: - between 3 % and 15% of retained austenite, - at least 30% of tempered martensite, having a C content of at most 0.45%, - at most 5% of fresh martensite, having a C content of at least 0.9%, - at most 35% of bainite, the bainite consisting of lower 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, 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%, - 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 100°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, at a cooling speed higher than 10°C/s, - between 3 % and 15% of retained austenite, - at least 30% of tempered martensite, having a C content of at most 0.45%, - at most 5% of fresh martensite, having a C content of at least 0.9%, - at most 35% of bainite, the bainite consisting of lower 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.