Method for producing a flat steel product provided with a metallic protective layer by hot-dip coating, comprising the following production steps: a) providing a cold-rolled or hot-rolled flat steel product which in addition to Fe and unavoidable impurities contains (in % wt.) up to 35.0 % Mn, up to 10.0 % Al, up to 10.0 % Si, up to 5 % Cr, up to 2.0 % Ni, up to 0.5 % of Ti, V, Nb, Mo respectively, up to 0.1 % S, P and N respectively, up to 1.0 % C and optionally 0.0005 - 0.01 % B; b) heating the flat steel product in a DFF-type preheating furnace in which a preoxidation section is formed and in which the flat steel product is exposed to an oxidising atmosphere, in order to form a covering FeO layer on the surface of the flat steel product, wherein burners are arranged in the preoxidation section which are operated with excess oxygen, and wherein at least one of the burners is assigned to the upper side of the flat steel product and at least another of the burners is assigned to the underside of the flat steel product; c) recrystallising annealing of the flat steel product in an annealing furnace which is passed through following the preheating furnace in order to bring about a recrystallisation of the flat steel product, wherein an annealing atmosphere having a reducing effect with respect to the FeO prevails in the annealing furnace; d) cooling the flat steel product down to a bath entry temperature in the range from 430 °C to 800 °C in a protective gas atmosphere; e) introducing the flat steel product into a molten bath, the temperature of which is in the range from 420 °C to 780 °C; and f) passing the flat steel product through the molten bath and setting the thickness of the metallic protective layer present on the flat steel product coming out of the molten bath, characterised in that flameless burners are used as burners in the preoxidation section of the preheating furnace, by means of which fuel, preferably burnable gas, and oxygen-containing gas are introduced into the preheating furnace separately from one another at a flow rate of at least 60 m/s, wherein in addition to at least one of the flameless burners assigned to the upper side of the flat steel product and in addition to at least one flameless burner assigned to the underside of the flat steel product, in each case at least one gas pipe is provided for supplying at least one additional gas flow, by means of which the fuel and the oxygen-containing gas are mixed in a complementary manner, and wherein the additional gas flow is introduced directed obliquely to the plane of the flat steel product into the preheating furnace. a) providing a cold-rolled or hot-rolled flat steel product which in addition to Fe and unavoidable impurities contains (in % wt.) up to 35.0 % Mn, up to 10.0 % Al, up to 10.0 % Si, up to 5 % Cr, up to 2.0 % Ni, up to 0.5 % of Ti, V, Nb, Mo respectively, up to 0.1 % S, P and N respectively, up to 1.0 % C and optionally 0.0005 - 0.01 % B; b) heating the flat steel product in a DFF-type preheating furnace in which a preoxidation section is formed and in which the flat steel product is exposed to an oxidising atmosphere, in order to form a covering FeO layer on the surface of the flat steel product, wherein burners are arranged in the preoxidation section which are operated with excess oxygen, and wherein at least one of the burners is assigned to the upper side of the flat steel product and at least another of the burners is assigned to the underside of the flat steel product; c) recrystallising annealing of the flat steel product in an annealing furnace which is passed through following the preheating furnace in order to bring about a recrystallisation of the flat steel product, wherein an annealing atmosphere having a reducing effect with respect to the FeO prevails in the annealing furnace; d) cooling the flat steel product down to a bath entry temperature in the range from 430 °C to 800 °C in a protective gas atmosphere; e) introducing the flat steel product into a molten bath, the temperature of which is in the range from 420 °C to 780 °C; and f) passing the flat steel product through the molten bath and setting the thickness of the metallic protective layer present on the flat steel product coming out of the molten bath, characterised in that flameless burners are used as burners in the preoxidation section of the preheating furnace, by means of which fuel, preferably burnable gas, and oxygen-containing gas are introduced into the preheating furnace separately from one another at a flow rate of at least 60 m/s, wherein in addition to at least one of the flameless burners assigned to the upper side of the flat steel product and in addition to at least one flameless burner assigned to the underside of the flat steel product, in each case at least one gas pipe is provided for supplying at least one additional gas flow, by means of which the fuel and the oxygen-containing gas are mixed in a complementary manner, and wherein the additional gas flow is introduced directed obliquely to the plane of the flat steel product into the preheating furnace.