He managed to wound eight and kill four before he was gunned down himself, according to the Rwandan Defence Ministry.
At first, the Ministry reported that the gunman committed suicide but then corrected their statement.
"The (Rwanda Defence Force) engaged the assailant soldier, killing him and saving the lives of other RDF peacekeepers," they said.
The UN mission in Central Africa — known as the MINUSCA force — comprises 10,800 troops drawn from Burundi, Cameroon, Congo, the Democratic Republic of Congo, Equatorial Guinea, Gabon, Rwanda, Morocco, Senegal, Pakistan and Indonesia.
The primary goal of the UN peacekeeping mission is to stop religious cleansing; however, avoiding violence within the Rwandan contingent's base appears not to be an easy task either.
The motives have yet to be determined, but the mission's representative, Brigadier General Joseph Nzabamwita, suggested it was most likely an act of terrorism.
"Investigations have immediately commenced to establish the motive behind this deplorable shooting," he said. "We suspect terrorism, without ruling out mental illness as the cause."
The injured soldiers were immediately taken to a hospital in Bangui for treatment.