The present invention relates to a composition for lightening keratin fibres, in particular human keratin fibres such as the hair, comprising (a) hydrogen peroxide； (b) one or more carbonates and/or one or more carbonate-generating systems in a content of greater than or equal to 0.2%, preferably greater than or equal to 0.3%, preferably greater than or equal to 0.5% and particularly greater than or equal to 1% by weight relative to the weight of the composition, (c) one or more polyphosphorus derivatives, in a total content of greater than or equal to 0.5% by weight, relative to the total weight of the composition, (d) one or more peroxygenated salts, said polyphosphorus derivative(s) being different from said peroxygenated salt(s), and the pH of the composition being less than or equal to 10, preferably less than or equal to 9.7 and better still from 6 to 9.5. The invention also relates to a lightening process using said composition, and also to a multi-compartment device which is suitable for using said lightening composition.
