Holding frame for receiving modular contact inserts, comprising - an opening into which at least one contact insert can be inserted in an insertion direction, - a frame wall (31, 32) which delimits the opening at least in sections and which has an edge (313, 323) and at least one recess (310, 320) which is formed in the edge (313, 323) and into which a protruding element (420, 421) of the contact insert can be pushed when a contact insert is inserted into the opening, and - a blocking element (35, 36, 38, 39) which is arranged on the side wall (31, 32) and has a clip section (350, 360, 380, 390) which - delimits the at least one recess (310, 320) against the insertion direction in a blocking position, in order to hold the protruding element (420, 421) of the contact insert in the recess (310, 320) against the insertion direction, and - can be moved out of the blocking position into a release position transversely in relation to the insertion direction for the purpose of releasing the protruding element (420, 421) for the purpose of removing the contact insert from the holding frame, - wherein the clip section (350, 360, 380, 390) extends transversely in relation to the insertion direction and engages over the at least one recess (310, 320) in the blocking position in such a way that the at least one recess (310, 320) is delimited against the insertion direction by the clip section (350, 360, 380, 390), wherein the blocking element (35, 36, 38, 39) is elastically resilient, characterized in that the blocking element (35, 36, 38, 39) is attached to the frame wall (31, 32) as a separate element, wherein the blocking element is attached to the frame wall (31, 32) in such a way that the blocking element engages around the frame wall (31, 32) at a second edge (314, 324) which is situated opposite the first edge (313, 323) which has the at least one recess (310, 320), wherein the blocking element, by way of a first surface section, bears against an outer side of the frame wall (31, 32), which outer side is averted from the opening, and, by way of a second surface section, bears against an inner side of the frame wall (31, 32), which inner side faces the opening, and the clip section is arranged on the first surface section. - an opening into which at least one contact insert can be inserted in an insertion direction, - a frame wall (31, 32) which delimits the opening at least in sections and which has an edge (313, 323) and at least one recess (310, 320) which is formed in the edge (313, 323) and into which a protruding element (420, 421) of the contact insert can be pushed when a contact insert is inserted into the opening, and - a blocking element (35, 36, 38, 39) which is arranged on the side wall (31, 32) and has a clip section (350, 360, 380, 390) which - delimits the at least one recess (310, 320) against the insertion direction in a blocking position, in order to hold the protruding element (420, 421) of the contact insert in the recess (310, 320) against the insertion direction, and - can be moved out of the blocking position into a release position transversely in relation to the insertion direction for the purpose of releasing the protruding element (420, 421) for the purpose of removing the contact insert from the holding frame, - wherein the clip section (350, 360, 380, 390) extends transversely in relation to the insertion direction and engages over the at least one recess (310, 320) in the blocking position in such a way that the at least one recess (310, 320) is delimited against the insertion direction by the clip section (350, 360, 380, 390), wherein the blocking element (35, 36, 38, 39) is elastically resilient, characterized in that the blocking element (35, 36, 38, 39) is attached to the frame wall (31, 32) as a separate element, wherein the blocking element is attached to the frame wall (31, 32) in such a way that the blocking element engages around the frame wall (31, 32) at a second edge (314, 324) which is situated opposite the first edge (313, 323) which has the at least one recess (310, 320), wherein the blocking element, by way of a first surface section, bears against an outer side of the frame wall (31, 32), which outer side is averted from the opening, and, by way of a second surface section, bears against an inner side of the frame wall (31, 32), which inner side faces the opening, and the clip section is arranged on the first surface section. - delimits the at least one recess (310, 320) against the insertion direction in a blocking position, in order to hold the protruding element (420, 421) of the contact insert in the recess (310, 320) against the insertion direction, and - can be moved out of the blocking position into a release position transversely in relation to the insertion direction for the purpose of releasing the protruding element (420, 421) for the purpose of removing the contact insert from the holding frame, - wherein the clip section (350, 360, 380, 390) extends transversely in relation to the insertion direction and engages over the at least one recess (310, 320) in the blocking position in such a way that the at least one recess (310, 320) is delimited against the insertion direction by the clip section (350, 360, 380, 390),