The rough framing dimensions of length, width, and height are given in multiples of 12.5 cm.
The DIN 4172 standard specifications titled “Dimensions in Construction (Maßordnung im Hochbau)”, differentiate between two types of construction methods:

Masonry with mortared head joints is a method of jointed construction. The nominal sizing for overall dimensions, add-on, and clear dimensions deviates about 1 cm from the rough framing dimensions.