A flat steel product, and a method for its production, which is formed from a steel substrate, such as strip or sheet steel, and a zinc-based corrosion protection coating, applied to at least one side of the steel substrate, which contains (in wt. %) Mg: 0.25 to 2.5%, Al: 0.2 to 3.0%, Fe: ≦4.0%, and optionally in total up to 0.8% of one or more elements of the group Pb, Bi, Cd, Ti, B, Si, Cu, Ni, Co, Cr, Mn, Sn and rare earths, remainder zinc and unavoidable impurities are described. The corrosion protection coating has an Al content of maximum 0.5 wt. % in an intermediate layer extending between a surface layer directly adjacent to the surface of the flat steel product and a border layer adjacent to the steel substrate and with a thickness amounting to at least 20% of the total thickness of the corrosion protection coating.