Paris has told the International Olympic Committee "it's now or never" as it bids for the 2024 Olympic and Paralympic Games.
Paris and Los Angeles are the two cities still competing to be the host in 2024 and there has been suggestions that the IOC may award both the 2024 and 2028 Games in September.
But Paris Olympic and Paralympic Games bid co-chair and IOC member Tony Estanguet insists the French capital would only host the Games it is bidding for.
We're okay if the IOC wants to give two Games at the same session in Lima," said Estanguet, speaking in London on Tuesday. "But on our side, our project is only possible for '24.
"We can't accept '28. It's not possible. It's now or never. Either the IOC family wants to choose Paris for '24 or we will not come back for '28."
Budapest, Hamburg and Rome have already left the race for 2024 over domestic concerns about costs.
Paris hosted the second Games in 1900 and again in 1924, but lost out to Barcelona in 1992, Beijing in 2008 and London four years later.
"This is the fourth bid, we learnt a lot," added Estanguet, a three-time Olympic slalom canoe gold medal winner. "We also believe this is the time to come back to Paris, or to Europe, in '24.
"We are not against the process, we welcome the process and understand the process, but our project is only possible for '24.
"We cannot imagine hosting the Games in '28. That was not the mandate I received from my team, the political leaders in my country.
"We believe we are the best partner for '24. It's a no risk bid."
Paris will largely make use of existing venues and infrastructure, but the site of the athletes' village, in Seine-Saint-Denis, is attached only to the 2024 bid and will not be available thereafter.
The French city and LA chiefs are poised to meet at next month's Sport Accord business and sport convention in Aarhus in Denmark, but there will be no compromise from Paris.
"We will meet them," Estanguet added. "There's no problem at all to discuss this and how they feel with this.
"But then again, it will not be possible for us to open any gate in discussing negotiating for '28. On our side it's really clear: we are only focused on '24."
Lessons have been learned from London's staging of the Games and Estanguet insists Paris would be a Games for the whole of Europe in a post-Brexit world.
"It was a great example for us. We looked very carefully at what London delivered," he said. "It was a similar approach.
"If Paris is host of the Games. It won't be only a French bid. It's really easy to come to Paris from different places in Europe.
"We hope to welcome British (people) to France in 2024."
