The Paris Olympics this year will generate an economic gain of 6.7-11.1 billion euros (7.2-11.9 billion dollars) for the capital region, according to a study commissioned by the organising committee released on Tuesday.

The research by the France-based Center for Law and Economics of Sport, an independent institute, modelled the impact of construction work, extra tourism and organising the event itself.

In their low-case scenario, the authors calculated a gain of 6.7 billion euros for the Paris region, rising to 11.1 billion in their highest projection.

Measuring the economic gains of so-called “mega-events” such as the football World Cup and the Olympics is notoriously difficult, and the authors urged caution about interpreting the results.

They stressed that the overall impact would be seen over a 17-year period beginning from the start of work in 2018 and until the end of the so-called “legacy period” in 2034.

The results are also to be compared against the overall size of the Paris economy, which was estimated at around 765 billion euros in 2021 by the French national statistics agency.

Measuring the impact of the Olympics is always difficult because some infrastructure spending and other building work might have been completed without the Games.

And the event can also have negative secondary effects at a national level, such as depressing consumer spending – which occurred in Britain during the 2012 Olympics – or deterring some tourists.

“The authors of this study would like to point out that an economic impact study alone cannot legitimise the hosting of an event and the expenditure involved,” the study said.

The governor of the French central bank, Francois Villeroy de Galhau, said in March that the biggest impact from the Games would be “psychological” rather than economic.

Organisers of the Paris Games and the International Olympic Committee see the July 26-August 11 event in the French capital as the star of a new low-impact and less extravagant model.

Only two new permanent sporting venues have been built in a bid to reduce the financial cost and carbon emissions.

The budget is also on track to be smaller than previous editions, with the latest estimate for nine billion euros, including 2.4 billion in public funds.

Some costs for the state, such as providing security and bonuses for public-sector staff, have not been finalised, however.

The CDES carried out a previous economic impact study for the Paris Games in 2016 in support of the city's bid for the event.

At the time, it estimated the economic gain at 5.3-10.7 billion euros.