Abstract: In order to bring about a single-handed actuation during the insertion operation of the buckle latch into a belt buckle arranged recessed in its non-use position in a pocket of a seat part, the pocket is lined by a shell and the shell is provided with a guide surface along which slides the emplaced buckle latch in the direction of the receiving funnel of the belt buckle. The guide surface may be provided with a guide groove for the positionally correct latch guidance. However, also a push button may extend therethrough whereby the stroke movement produced by actuation by the belt latch is transmitted onto the belt buckle by means of a transmission device.