Mounting plate (1) for a lavatory body (2) of a washlet, comprising: a building-side installation surface (3); a front installation surface (4) for connecting to a lavatory body (2); at least one opening (23, 24) for leading through a flushing water supply and an outflow; means (29) for fastening the mounting plate (1) to a building wall; a first and a second supporting element (8, 9) which are designed as plug elements for pluggable mounting of a lavatory body (2) onto the mounting plate (1); an electrical plug connector (46) arranged on the front installation surface (4); and a water supply connection piece (43). Lavatory body (2) for pluggable mounting onto a mounting plate (1), comprising two or more horizontally spaced-apart guide elements (15) which are fastened in the cavity (14) to the ceramic body (20) and are designed for pluggable connection to supporting elements (8, 9) on a mounting plate (1); and a bidet device (30) with an electric connection (31) which is fixedly arranged on the lavatory body (2) and is designed as a plug connector accessible from the rear side (13) of the ceramic body (20).