A plug connector for connecting lines for liquid and/or gaseous media to a second plug connector thus forming a plug assembly, the first plug connector comprising - a plug connector body, which plug connector body is tubular and made of a plastic material and a longitudinal axis extends between a first end region and a second end region, - a receiving sleeve, which receiving sleeve is formed from a metallic material and is arranged on the outside in the first end region of the plug connector body and is held fixedly on the plug connector body, and the receiving sleeve projects beyond the plug connector body on the side facing away from the second end region, wherein a female receiving space is defined jointly by the plug connector body and the receiving sleeve, and wherein at least the receiving space is configured to be hollow-cylindrical, - a sealing element, which sealing element is configured to be annular and is arranged in the receiving space defined by the plug connector body and the receiving sleeve and is held in a receiving groove with a first groove side face, a second groove side face and a groove base face positioned in the direction of the longitudinal axis, - wherein the first groove side face and at least a partial section of the groove base face of the receiving groove are formed by the plug connector body, - wherein the second groove side face is formed by a first wall section of the receiving sleeve, which first wall section is an integral part of the receiving sleeve, and - wherein the first wall section in the region of the second groove side face has an orientation directed in the direction of the longitudinal axis with respect to the longitudinal axis extending in the region of the receiving space, - wherein the first wall section is supported in contact with an end face of the connector body, characterized in that a third wall section of the receiving sleeve is provided, which third wall section is configured to be hollow-cylindrical and is arranged at a second wall section end of the first wall section facing away from the longitudinal axis with respect to the longitudinal axis extending in the region of the receiving space and is connected to said second wall section end, and that the third wall section is arranged to project on the side facing away from the connector body and ends at a first receiving sleeve end. - a plug connector body, which plug connector body is tubular and made of a plastic material and a longitudinal axis extends between a first end region and a second end region, - a receiving sleeve, which receiving sleeve is formed from a metallic material and is arranged on the outside in the first end region of the plug connector body and is held fixedly on the plug connector body, and the receiving sleeve projects beyond the plug connector body on the side facing away from the second end region, wherein a female receiving space is defined jointly by the plug connector body and the receiving sleeve, and wherein at least the receiving space is configured to be hollow-cylindrical, - a sealing element, which sealing element is configured to be annular and is arranged in the receiving space defined by the plug connector body and the receiving sleeve and is held in a receiving groove with a first groove side face, a second groove side face and a groove base face positioned in the direction of the longitudinal axis, - wherein the first groove side face and at least a partial section of the groove base face of the receiving groove are formed by the plug connector body, - wherein the second groove side face is formed by a first wall section of the receiving sleeve, which first wall section is an integral part of the receiving sleeve, and - wherein the first wall section in the region of the second groove side face has an orientation directed in the direction of the longitudinal axis with respect to the longitudinal axis extending in the region of the receiving space, - wherein the first wall section is supported in contact with an end face of the connector body,