Contact elements and plug-in connectors, in particular for cable harnesses

A contact element having a front box section for insertion into a chamber of a plug-in connector body, and a rear connection section to which an electric lead can be attached, the front box section having a first latching element which can make a latching connection with a complementary second latching element of the plug-in connector body, in order to hold the contact element non-displaceably in the body, wherein the first latching element is arranged in a flexible tongue of the front box section which can be moved perpendicularly with respect to a plugging-in direction, in order to release the latching connection between said first and second latching element, and wherein the tongue extends in a plugging-in direction and has a free end approximately at a front end of the front box section, and the first latching element is a window adapted to receive a lug of said connector body therein.