Abstract: The invention relates to a plant for packaging a gas mixture in one container (10), comprising a source of a minor gas (1), a source of a carrier gas (2), a mixer device (3), a first transfer circuit (6) fluidically connecting the source of minor gas (1) to the mixer device (3) and comprising a first flow regulator device (4), a second transfer circuit (7) fluidically connecting the source of a carrier gas (2) to the mixer device (3), a delivery circuit (8) comprising a second flow regulator device (9), the first transfer circuit (6) and the second transfer circuit (7) each include an expansion member (15, 16), the second flow regulator device (9) comprising a pressure raising member (9), the first flow regulator device (4) comprising several regulator members.