With the blessing of the 130th IOC Session that met in Lausanne in July, the IOC, Los Angeles, Paris and their National Olympic Committees have been working together in order to reach the agreement that was ratified by the IOC Session today.
Both cities made presentations in their bids for hosting the games.
The 2024 Games will mark the third time Paris has staged the Olympics, coming exactly 100 years after they last hosted the Games.
It mirrored a similar trend in the bidding for the 2022 Winter Olympics, when only two cities Beijing and Almaty threw their hats into the ring.
"This is a momentous day for the people of Los Angeles and the United States", Los Angeles Mayor Eric Garcetti said in a USOC release.
The Mayor of Paris, Anne Hidalgo, said: "Today I am delighted to invite you to join the great family of Parisians, a family which belongs to the world".
Paris insisted it didn't want to wait around for the opportunity, pouncing on the chance to host sooner than later.
The Olympic body, however, was eager to secure the future of its prime product even if it meant handing out two editions at the same time after Boston, Budapest, Rome and Hamburg all pulled the plug on their bids mid-race, fearing high costs and local opposition.
"This historic double allocation is a "win-win-win" situation for the city of Paris, the city of Los Angeles and the IOC". After the IOC's 2024 Evaluation Commission visited L.A. and Paris in May 2017, it issued a report praising both cities and describing L.A.'s bid as "forward-looking, innovative and vibrant".
Tokyo, the host of the next summer Games in 2020, has also had to fend off allegations of corruption regarding the decision to award it the Games four years ago. Although an independent analysis of a budget for 2028 will not likely be completed for months, it is not expected to vary drastically in cost or approach and the L.A. City Council approved the switch to '28 in August despite not having a complete picture of the financial aspects of the decision.
The LA Games have a budget of $5.3 billion and will essentially follow the plan they had in place for 2024, including housing athletes at the UCLA campus.
The cauldron was lit early Wednesday morning at the stadium that was the site of the 1932 and 1984 Olympics.
Paris also has a planned $1.44 billion Olympic Village that will be located near the River Seine.