The election by the IOC of an Olympic city is unlike anything known. It is preceded by a two-year campaign, during which candidates break the bank, going so far as to spend a good hundred million euros on lobbying, communication, studies and preparation of the file. On the big day, the ceremonial is organized like a ballet. A few hours before the vote by the city's Olympic institution for the 2020 Summer Games, scheduled for this Saturday, September 7 in Buenos Aires, a short explanation of the voting method is necessary.

The presentations. Istanbul, Madrid and Tokyo will be entitled, before the vote, to a presentation of their file before the IOC General Assembly. This presentation should not last more than 45 minutes. It is followed by a question/answer session. The draw thus determined the order of appearance of the three candidates (in parentheses, the time of their presentation in French time): Istanbul (14 p.m. – 15:10 p.m.), Tokyo (15:30 p.m. – 16:40 p.m.) , Madrid (17 p.m. – 18:10 p.m.).

The electors: the IOC currently has 103 members, including its president, Jacques Rogge. But the latter most often abstains from taking part in the vote. IOC members belonging to one of the countries concerned by this election (3 Spaniards, 1 Turk and 1 Japanese) cannot vote as long as the city representing their country is in the race.

Voting: the vote, by secret ballot, is done electronically. A voter can only vote for one city. The city which receives an absolute majority – abstentions, blank or invalid votes are not taken into account in the calculation – is elected. If an absolute majority is not reached in the first round, the city having received the fewest votes is eliminated. The counters are reset to zero and a second round is organized between the two remaining candidates. In Buenos Aires, voting is scheduled between 20:45 p.m. and 21 p.m. (French time).

The results. They are announced by Jacques Rogge. The IOC President will appear at the podium, to open the mystery envelope and announce on the microphone the name of the city of the 2020 Games. This announcement is scheduled between 22 p.m. and 22:30 p.m. It will be followed by a signature contract of the Olympic city and a joint press conference of the IOC and the lucky elected officials. The result, analyzes and details of the vote can be found on FrancsJeux throughout the evening