Refrigeration plant with multiple evaporation levels, operating according to a vapour compression cycle and comprising a circuit having a high-pressure branch, in which at least one heat exchanger is arranged, which functions as a condenser or gas cooler, and two or more low-pressure branches (LP1, LP2, LP3), each of which operates at a different evaporation level to serve users having different refrigeration requirements, in each low-pressure branch (LP1, LP2, LP3) said plant comprising an expansion device (11', 11", 11"'), at least one evaporator (12', 12", 12"') and a compressor group (13', 13", 13"'), wherein said at least one evaporator of each low-pressure branch (LP1, LP2, LP3) is connected directly to said high-pressure branch by means of the respective expansion device (11', 11", 11"'), at least a first low-pressure branch operating at a first evaporation level comprising a liquid separator that is fluidically connected: - to the evaporator outlet of said first low-pressure branch to collect the liquid exiting the evaporator in case the latter is operating in overfeeding conditions; and - to the intake of the compressor group of said first low-pressure branch; characterised in that said liquid separator is not fluidically connected to the inlet of the evaporator of said first low-pressure branch, but is fluidically connected to a second low-pressure branch operating at a second evaporation level lower than the first upstream of the expansion device (11") of this second low-pressure branch through a first connection duct, and in that said circuit comprises first valve means (22", 23') that are installed in the first connection duct and in the second low-pressure branch and are controllable in such a way that said second low-pressure branch is alternately fed by the high-pressure branch or by said liquid separator through said first connection duct, said first valve means (22", 23') being actuated to allow feeding the evaporator (12") of the second low-pressure branch with liquid coming from the liquid separator of the first evaporation branch when the evaporator of the first evaporation branch is made to operate in overfeeding conditions so as to discharge the liquid that collects in said liquid separator, wherein said first valve means (22", 23') comprise: - a first valve (22") of connection between the high-pressure branch and the second low-pressure branch and a second valve installed on said first connection duct, preferably said first valve (22") being an on-off valve and said second valve being a non-return valve, or - a three-way valve, which connects the second low-pressure branch alternately to the high-pressure branch and to the first connection duct, wherein the high pressure branch comprises a liquid receiver arranged downstream of the heat exchanger, and wherein the vapour compression cycle uses CO2 as refrigerant, the high-pressure branch comprising an expansion device arranged between the heat exchanger, which functions as a condenser or gas cooler, and the liquid receiver. - to the evaporator outlet of said first low-pressure branch to collect the liquid exiting the evaporator in case the latter is operating in overfeeding conditions; and - to the intake of the compressor group of said first low-pressure branch; characterised in that said liquid separator is not fluidically connected to the inlet of the evaporator of said first low-pressure branch, but is fluidically connected to a second low-pressure branch operating at a second evaporation level lower than the first upstream of the expansion device (11") of this second low-pressure branch through a first connection duct, and in that said circuit comprises first valve means (22", 23') that are installed in the first connection duct and in the second low-pressure branch and are controllable in such a way that said second low-pressure branch is alternately fed by the high-pressure branch or by said liquid separator through said first connection duct, said first valve means (22", 23') being actuated to allow feeding the evaporator (12") of the second low-pressure branch with liquid coming from the liquid separator of the first evaporation branch when the evaporator of the first evaporation branch is made to operate in overfeeding conditions so as to discharge the liquid that collects in said liquid separator, wherein said first valve means (22", 23') comprise: - a first valve (22") of connection between the high-pressure branch and the second low-pressure branch and a second valve installed on said first connection duct, preferably said first valve (22") being an on-off valve and said second valve being a non-return valve, or - a three-way valve, which connects the second low-pressure branch alternately to the high-pressure branch and to the first connection duct, wherein the high pressure branch comprises a liquid receiver arranged downstream of the heat exchanger, - a first valve (22") of connection between the high-pressure branch and the second low-pressure branch and a second valve installed on said first connection duct, preferably said first valve (22") being an on-off valve and said second valve being a non-return valve, or - a three-way valve, which connects the second low-pressure branch alternately to the high-pressure branch and to the first connection duct, wherein the high pressure branch comprises a liquid receiver arranged downstream of the heat exchanger, and wherein the vapour compression cycle uses CO2 as refrigerant, the high-pressure branch comprising an expansion device arranged between the heat exchanger, which functions as a condenser or gas cooler, and the liquid receiver.