The invention relates to a method for separating a hydrocarbon mixture (C), which is obtained at least in part by steam cracking (10) and which contains at least hydrocarbons having one, two and three carbon atoms, including ethane and ethylene, a first fraction (C2+, C2−) initially being obtained from the hydrocarbon mixture (C) by separating off other components at least in part, said fraction containing the predominant part of the hydrocarbons having two or more carbon atoms previously contained in the hydrocarbon mixture (C) or the predominant part of the hydrocarbons having two or fewer carbon atoms previously contained in the hydrocarbon mixture (C), further fractions (C1, C2, C2H4, C3+, C2H6) subsequently being obtained from the first fraction (C2+, C2−). A fraction (R, S) containing ethane is separated off, in parallel with or downstream from the at least partial separation of the other components from the hydrocarbon mixture (C), in an amount which reduces the ethane content in the first fraction (C2+, C2−) to less than 25%, the fraction (R, S) containing ethane being low in or free from other hydrocarbons having two carbon atoms. The present invention further relates to a separation system (30), to a corresponding steam cracking system and to a method for retrofitting a steam cracking system.