The 24-year-old was seemingly knocked unconscious following a tackle in the Saints' defeat to Leicester Tigers in December, before being cleared to continue playing.
North was then stood down from duty while an independent assessment process was conducted, which concluded with the Wales international's club side escaping any sort of sanction.
However, World Rugby made it clear last month that they intended to speak with the Rugby Football Union and Premiership Rugby over the decision not to challenge the Saints' conduct.
Following the discussions, the governing body released a statement that read: "Despite the failing by the club to correctly apply World Rugby's head-injury management protocols, World Rugby has recognised that the RFU and PRL acted swiftly and appropriately to implement measures with Northampton Saints and other clubs to reduce the probability of future non-compliance."
"While it is impossible to completely remove the risk of error, World Rugby remains disappointed that there was a failure in this case to identify and manage the injury appropriately, in particular considering North's medical history."
World Rugby concluded that it was "satisfied" with the club's medical department, who have since been educated on the removal process of a player in such a scenario.