Scouring the internet and aviation websites, I came across the British Airways offer. More precisely, I found a very good price for Bucharest - Johannesburg, 514 €. Since writing about airline promotions, I haven't seen this fare for South Africa. This price can be found in September 2015.
Below is a simulation for September 9 - September 14! It is for informational purposes!
The short flights to Bucharest - London - Bucharest are operated by Airbus A320 aircraft, and the flights Johannesburg - London - Johannesburg by Airbus A380 super jumbo. Another plus to take advantage of this offer.
On 4 July 2013, British Airways has acquired the first Airbus A380 in the fleet. Starting with 12 February 2014, British Airways introduced Airbus A380 on the London - Johannesburg route. At that time, the prices of round-trip tickets from London started from 1010 Euro in the World Traveler cabin (economic), from 1600 Euro in the World Traveler Plus cabin (higher economy), from 3791 Euro in the Club World cabin (business) and 7156 Euro in the First cabin. Now you have the opportunity to fly Bucharest - Johannesburg from 514 euros.