Abstract: A plug connector includes a housing, a locking element and a verification element. The housing has a receiving chamber, a connection piece and a duct through which fluid can flow. The locking element is movable between an open position and a fastening position, a plug can be inserted in the receiving chamber in the open position of the locking element, and a plug inserted in the receiving chamber can be fastened within the receiving chamber via the locking element in the fastening position of the locking element. In an open position of the locking element, the verification element is at least partially covered by the locking element, and in a fastening position of the locking element, the verification element can be read.