The trio of Racing 92 imports were cleared last October by the French Rugby Federation after traces of corticosteroids were found in tests following the Top 14 final in Barcelona last June.
But Le Monde has reported that the French anti-doping agency, The College of the AFLD, now wants a please explain from the players over the incident.
The French newspaper reported the development was "not rare".
When Le Monde approached Racing 92 about the reported development, the glamour Paris club refused to comment.
Le Monde suggested AFLD experts wanted to determine if the rates are consistent with the treatments reported by the club doctor and the methods the corticosteroids had been administered.
Fellow French paper L'Equipe also carried coverage.
Racing won the final against Toulon 29-21.
After the revelations that the three players had tested positive for corticosteroids, which are prohibited unless the player(s) have been granted a Therapeutic Use Exemption (TUE) by the authorities, the club released a statement stating: "It was treatment administered in an authorised manner, given in response to a proven condition several days before the Top 14 final and not requiring a TUE (Therapeutic Use Exemption).
"All the medical procedures on the players reported by the media were carried out in total respect of the national and international anti-doping rules."
That eventually proved to be the finding of the French rugby inquiry after Carter and Rokocoko expressed their horror and vowed to clear their names.