The invention relates to a method for processing waste paper according to the following steps: a) the waste paper is decomposed into fibres, b) the fibres are washed, c) the fibres are subjected to a dispersion process, d) the fibres are subjected to a flotation method, e) the fibres are processed for further treatment in a paper machine. The liquid from the fibres obtained in step b) is reintroduced into the fibre flow prior to step d). The invention also relates to a device for carrying out said method.