Method of recovering carbon fibers from carbon fiber-containing plastics, in particular of carbon fiber reinforced plastic, preferably of carbon fiber-containing and/or carbon fiber-reinforced composite materials, wherein an object based on a plastic containing carbon fibers comprises carbon fiber in a plastic matrix and is subjected to multistep pyrolysis in the presence of oxygen, wherein the plastic of the plastic matrix is decomposed during the pyrolysis in order to obtain the carbon fibers: wherein the pyrolysis is carried out in a pyrolysis apparatus P, wherein the pyrolysis apparatus P comprises at least the following treatment zones in the sequence specified below and wherein the object passes through the subsequent treatment zones in the following sequence: a heating zone A, in which the object to be treated and/or recycled is heated to a defined temperature T, then a first pyrolysis zone B1, in which a pyrolysis of the plastic of the plastic matrix of the object to be treated is carried out at a given temperature T and a defined oxygen content G, and/or, then a second pyrolysis zone B2, in which a final pyrolysis of the plastic of the plastic matrix of the object to be treated remaining after the pyrolysis B1 is carried out at a given temperature T and a defined oxygen content G up to at least substantially complete removal, then a cooling zone C for the cooling of the recycled RF carbon fiber received from the second pyrolysis zone B2; wherein the oxygen content G in the second pyrolysis zone B2 is increased compared to the oxygen content G in the first pyrolysis zone B1 and wherein the temperature T in the second pyrolysis zone B2 is increased compared with the temperature T in the first pyrolysis zone B1, wherein the oxygen content G in the first pyrolysis zone B1 is adjusted in the range of 0.1 vol.-% to 12 vol.-%, while the oxygen content G in the second pyrolysis zone B2 is adjusted in the range of 3 vol.-% to 20 vol.-%, but with the proviso that the oxygen content of G in the second pyrolysis zone B2 is increased compared to the oxygen content G in the first pyrolysis zone B1 by 3 vol.-% to 15 vol.-%, and wherein the temperature T in the second pyrolysis zone B2 is increased compared to the temperature T in the first pyrolysis zone B1 by 25 °C to 300 °C. wherein the pyrolysis is carried out in a pyrolysis apparatus P, wherein the pyrolysis apparatus P comprises at least the following treatment zones in the sequence specified below and wherein the object passes through the subsequent treatment zones in the following sequence: a heating zone A, in which the object to be treated and/or recycled is heated to a defined temperature T, then a first pyrolysis zone B1, in which a pyrolysis of the plastic of the plastic matrix of the object to be treated is carried out at a given temperature T and a defined oxygen content G, and/or, then a second pyrolysis zone B2, in which a final pyrolysis of the plastic of the plastic matrix of the object to be treated remaining after the pyrolysis B1 is carried out at a given temperature T and a defined oxygen content G up to at least substantially complete removal, then a cooling zone C for the cooling of the recycled RF carbon fiber received from the second pyrolysis zone B2; a heating zone A, in which the object to be treated and/or recycled is heated to a defined temperature T, then a first pyrolysis zone B1, in which a pyrolysis of the plastic of the plastic matrix of the object to be treated is carried out at a given temperature T and a defined oxygen content G, and/or, then a second pyrolysis zone B2, in which a final pyrolysis of the plastic of the plastic matrix of the object to be treated remaining after the pyrolysis B1 is carried out at a given temperature T and a defined oxygen content G up to at least substantially complete removal, then a cooling zone C for the cooling of the recycled RF carbon fiber received from the second pyrolysis zone B2; wherein the oxygen content G in the second pyrolysis zone B2 is increased compared to the oxygen content G in the first pyrolysis zone B1 and wherein the temperature T in the second pyrolysis zone B2 is increased compared with the temperature T in the first pyrolysis zone B1, wherein the oxygen content G in the first pyrolysis zone B1 is adjusted in the range of 0.1 vol.-% to 12 vol.-%, while the oxygen content G in the second pyrolysis zone B2 is adjusted in the range of 3 vol.-% to 20 vol.-%, but with the proviso that the oxygen content of G in the second pyrolysis zone B2 is increased compared to the oxygen content G in the first pyrolysis zone B1 by 3 vol.-% to 15 vol.-%, and wherein the temperature T in the second pyrolysis zone B2 is increased compared to the temperature T in the first pyrolysis zone B1 by 25 °C to 300 °C.