A stamp issue was planned for the laying of the foundation stone ("Pose de la Première Pierre") of the University of Dahomey in Calavi in 1970. Since the original schedule could not be kept and the event then took place on November, 6, 1970, the stamp was issued on that day. In the course of this, however, an over-print “Calavi-6-II-1970” was applied to the stamp.

The original stamp was therefore not issued. However, there are also cancelled copies of the original stamp, so that at least some original stamps were "misused", certainly against postal regulations. Furthermore, only a limited quantity of the original stamps were apparently over-printed. In later years (1986, 1992, 2008) the original stamps were issued in the renamed Benin with different overprints.