Process for the production of high-purity paraxylene from a xylenes cut containing ethylbenzene and C9+ compounds, a process using two simulated moving bed separation units (SMB-1 et SMB-2), and two isomerization units (ISOM-1 et ISOM-2) consisting of the following series of stages: - the feedstock is sent to a distillation column (S-1) from where a mixture is drawn off at the top comprising the major part of the metaxylene, paraxylene, ethylbenzene, and at least a part of the orthoxylene, and from where a flow of C9-C10 hydrocarbons and the remaining part of the orthoxylene is drawn off at the bottom. - the mixture from the top is separated in the separation unit (SMB-1) comprising at least one adsorber containing a plurality of interconnected beds and operating in a closed loop, said adsorber comprising at least five zones delimited by the injections of the flow and of the desorbent, and a first extract containing paraxylene, a first intermediate raffinate containing ethylbenzene, and a first raffinate-2 containing orthoxylene and metaxylene are drawn off, - a simulated moving bed separation of the isomerate originating from the isomerization unit (ISOM-1), is carried out in the separation unit (SMB-2) constituted by at least one adsorber containing a plurality of interconnected beds and operating preferentially in a closed loop, and said adsorber comprising at least five zones delimited by the injections of the flow and of the desorbent, and a second extract containing paraxylene, a second intermediate raffinate containing ethylbenzene, and a second raffinate-2 containing orthoxylene and metaxylene are drawn off, - the first extract originating from the separation unit (SMB-1) is distilled in a distillation column (EXT-1), in order to recover a first fraction enriched with paraxylene, - the two raffinates-2, flows and, are mixed in order to form the flow which is distilled in a column (RAF-2) so as to eliminate substantially all the desorbent, and in order to draw off a first distilled fraction, - a first isomerization unit (ISOM-1) is supplied with the flow, in order to obtain the first isomerate, - the two intermediate raffinates, flows and, are mixed in order to form the flow which is distilled in a column (RAFINTER) in order to substantially eliminate all of the desorbent and in order to draw off a second distilled fraction, - a second isomerization unit (ISOM-2) is supplied with the flow, in order to obtain a second isomerate, which is recycled to the inlet of the separation column (S-1). - the feedstock is sent to a distillation column (S-1) from where a mixture is drawn off at the top comprising the major part of the metaxylene, paraxylene, ethylbenzene, and at least a part of the orthoxylene, and from where a flow of C9-C10 hydrocarbons and the remaining part of the orthoxylene is drawn off at the bottom. - the mixture from the top is separated in the separation unit (SMB-1) comprising at least one adsorber containing a plurality of interconnected beds and operating in a closed loop, said adsorber comprising at least five zones delimited by the injections of the flow and of the desorbent, and a first extract containing paraxylene, a first intermediate raffinate containing ethylbenzene, and a first raffinate-2 containing orthoxylene and metaxylene are drawn off, - a simulated moving bed separation of the isomerate originating from the isomerization unit (ISOM-1), is carried out in the separation unit (SMB-2) constituted by at least one adsorber containing a plurality of interconnected beds and operating preferentially in a closed loop, and said adsorber comprising at least five zones delimited by the injections of the flow and of the desorbent, and a second extract containing paraxylene, a second intermediate raffinate containing ethylbenzene, and a second raffinate-2 containing orthoxylene and metaxylene are drawn off, - the first extract originating from the separation unit (SMB-1) is distilled in a distillation column (EXT-1), in order to recover a first fraction enriched with paraxylene, - the two raffinates-2, flows and, are mixed in order to form the flow which is distilled in a column (RAF-2) so as to eliminate substantially all the desorbent, and in order to draw off a first distilled fraction, - a first isomerization unit (ISOM-1) is supplied with the flow, in order to obtain the first isomerate, - the two intermediate raffinates, flows and, are mixed in order to form the flow which is distilled in a column (RAFINTER) in order to substantially eliminate all of the desorbent and in order to draw off a second distilled fraction, - a second isomerization unit (ISOM-2) is supplied with the flow, in order to obtain a second isomerate, which is recycled to the inlet of the separation column (S-1).