Electoral system for the president

Constitution of 2005

https://www.constituteproject.org/constitution/Burundi_2005.pdf

Article 102 

The election of the President of the Republic takes place in a uninominal ballot in tworounds.The President of the Republic is elected by an absolute majority of the suffrageexpressed. If this is not obtained in the first round, it proceeds, in a time period offifteen days, to a second round.Only the two candidates who have obtained the greater number of votes in the firstround may present themselves in the second round of the ballot. In the case ofwithdrawal [d?ssistement] of one or the other of the two candidates, the followingcandidates present themselves in the order of their ranking after the first ballot.The candidate having received the relative majority of the suffrage expressed isdeclared elected in the second round.