Might this be it (from Manuscripts, second MS., Estranged Labor)?
An enforced rise in wages (disregarding all other difficulties, including the fact that such an anomalous situation could only be prolonged by force) would therefore be nothing more than better pay for slaves and would not mean an increase in human significance or dignity for either the worker or the labor. Even the equality of wages,which Proudhon demands, would merely transform the relation of the present-day worker to his work into the relation of all men to work. Society would then be conceived as an abstract capitalist