The deal was described by IOC President Thomas Bach as a "win-win-win" agreement for both cities and the Olympic movement.
Paris had remained insistent on hosting in 2024, on the 100th anniversary of the city's 1924 Olympics.
He won gold in synchronised 3M springboard competition at 2012 London Olympics
Paris has maintained a tougher line on the 2028 question, insisting it was focused narrowly on 2024.
"We are committed to supporting the IOC in the valuable work they are doing to improve the quality of life of young refugees around the world through sport."
Figures released last month showed organisers had trimmed budget
The competition will be held in Pyeongchang from February 9 to 25
The organisers of the 2016 Rio Olympics denied that vote buying helped to secure the Games after a French newspaper reported that a Brazilian businessman made payments to the son of an IOC member before the vote.
The Hungarian capital's decision leaves the battle to stage the 2024 Games between Paris and Los Angeles.
More than 266,000 sign petition against Games
Russia was stripped of their women's 4 x 400m relay silver medal after Antonina Krivoshapka tested positive for drugs in the re-testing of her sample
Alibaba, which becomes the official e-commerce and cloud services partner, joins 12 other companies.
The IOC said it took the decision after they tested positive for prohibited substances.
Romanian weightlifter Gabriel Sincraian and Russian boxer Misha Aloian have been stripped of their 2016 Olympic medals after failing doping tests at the Games, the Court of Arbitration for Sport said.
Ten more athletes, mostly weightlifters and wrestlers, have been stripped of the medals they won at the 2008 Beijing Olympics after failing doping tests in re-testing of samples.