The French defender ruptured the anterior cruciate ligament in his right knee during the recent 5-0 win over Crystal Palace.
After initial tests in Manchester, Benjamin travelled to Barcelona to see Dr Ramon Cugat, a specialist doctor, to establish the extent of the injury.
And on Friday, he underwent surgery, which was completed without any problems.
Everyone at the Club wishes Benjamin a speedy recovery and we hope to see him back in the first team as soon as possible.
ManCity.com will bring you updates on his recovery as we get them.