Treatment installation for treating a series of containers, comprising: - at least one initial treatment machine for the initial treatment of the series of containers, in which the series of containers are subjected to an initial treatment between an entry point and an exit point of said initial treatment machine, - at least one first additional treatment machine and a second additional treatment machine for the additional treatment of the series of containers, said first and second additional treatment machines each being arranged such that at least a portion of the series of containers that have been subjected to the initial treatment are subjected to an additional treatment in the first additional treatment machine and/or in the second additional treatment machine, said additional treatment being applied between an entry point (34, 36) and an exit point (46, 58) of each of said first and second additional treatment machines (8, 10), - at least one first transfer device arranged so as to collect the series of containers at the exit point of the initial treatment device and to selectively distribute them to the entry point (34, 36) of the first and/or the second additional treatment machine (8, 10), the treatment installation being equipped - with a first exit from the installation, through which containers treated by the first additional treatment machine can exit, and - with a second exit from the installation, through which containers treated by the second additional treatment machine can exit, the first and the second exit from the installation being separate from one another, characterized in that the installation further comprises a second transfer device which can be actuated between an inactive configuration and an active configuration, the second transfer device in the active configuration being arranged so as to collect the series of containers at the exit point of the first additional treatment machine and to transfer them to the second additional treatment machine. - at least one initial treatment machine for the initial treatment of the series of containers, in which the series of containers are subjected to an initial treatment between an entry point and an exit point of said initial treatment machine, - at least one first additional treatment machine and a second additional treatment machine for the additional treatment of the series of containers, said first and second additional treatment machines each being arranged such that at least a portion of the series of containers that have been subjected to the initial treatment are subjected to an additional treatment in the first additional treatment machine and/or in the second additional treatment machine, said additional treatment being applied between an entry point (34, 36) and an exit point (46, 58) of each of said first and second additional treatment machines (8, 10), - at least one first transfer device arranged so as to collect the series of containers at the exit point of the initial treatment device and to selectively distribute them to the entry point (34, 36) of the first and/or the second additional treatment machine (8, 10), the treatment installation being equipped - with a first exit from the installation, through which containers treated by the first additional treatment machine can exit, and - with a second exit from the installation, through which containers treated by the second additional treatment machine can exit, the first and the second exit from the installation being separate from one another,