A process for producing leather comprises treating part-processed hides, crust leathers or pelts with at least one aqueous float comprising (A) at least one amphiphilic organic copolymer, (B) at least one silicone compound having at least one carboxylic acid group or at least one carboxylic anhydride group per molecule, (C) at least one surface-active compound selected from emulsifiers having at least one phosphorus atom per molecule, (D) at least one surface-active compound selected from N-acylated amino acids, (E) at least one surface-active compound comprising at least one C10-C30-alkyl radical, branched or unbranched, or at least one polyisobutene moiety, and at least one ionic or aqueous-ionizable group, other than amphiphilic copolymer (A) and surface-active compound (C), and which is free of waxes and oils.