Scanning force microscopy investigations on the triglycine sulfate (010) surface were carried out employing the method of matched faces. The difference in the etch rate of surfaces of ferroelectric domains with opposite polarity as observed with optical microscopy and scanning electron microscopy could be confirmed. The shape of the etch products on domains with equal polarity on the matching surfaces was found to vary widely. The height and direction of steps at the domain boundaries were measured and discussed with respect to earlier work done by means of transmission electron microscopy. A model which explains the differences in the step heights at the domain boundaries is given under consideration of the shift in the atom positions during ferroelectric polarization reversal.