France's World Cup final preparations were rocked as three more players were forced to miss training with cold-like symptoms on Friday just two days before their showdown with Argentina.

Raphael Varane, Ibrahima Konate and Kingsley Coman were all sidelined as Les Bleus prepare to take on Lionel Messi and Argentina in Sunday's final at Doha's Lusail Stadium.

The trio of absentees sparked further fears of a mystery virus in the French camp after two players -- Adrien Rabiot and Dayot Upamecano -- were ruled out of the semi-final win over Morocco.

Rabiot and Upamecano both returned to training on Friday.

Coman, the Bayern Munich winger, had already been forced to miss a training session on Thursday because of a "light viral syndrome", the French Football Federation (FFF) said.

France forward Randal Kolo Muani sought to play down the illnesses on Friday.

"There is little bit of flu going around but nothing serious," he said.

Earlier this week, France coach Didier Deschamps suggested frigid air conditioning might be to blame for the illnesses in the French squad.

"The air conditioning is on all the time and so we have had a few cases of flu-like symptoms but we will try to avoid it spreading," Deschamps said.

"The players put in so much effort on the pitch and so their immune systems suffer. Your body is weakened and you are more prone to getting infected."

France are aiming to become the first team to win back-to-back World Cups since Brazil achieved the feat in 1962 as Argentina captain Messi looks to crown his glorious career with the one major title that has eluded him.

Anticipation for the showdown between the European and South American heavyweights is reaching fever pitch, with the cheapest tickets on the secondary market changing hands for more than $4,000.

On Friday, Argentina fans who have flooded into Qatar for the tournament staged a second day of demonstrations outside a Doha hotel, demanding their country's national federation help them find tickets for Sunday's showpiece.

Cintia Echanis, 51, told AFP the protesters wanted access to tickets at face value.

"We don't want problems. What we want as Argentines is to have the chance to cheer for Argentina again," she said.

Sunday's final will bring the month-long football tournament, one of the most controversial World Cups in history, to a close.

FIFA president Gianni Infantino shrugged off criticism of the event on Friday, describing it as the "best World Cup ever".

"The World Cup has been an incredible success on all fronts," Infantino added.

"The main one being the fans, the behaviour, the joyful atmosphere, the bringing of people together. The fans meeting the Arab world, it has been very important for the future of all of us."

Infantino said the tournament had exceeded revenue predictions in the four-year cycle leading to 2022, rising to a record $7.5 billion -- $1 billion more than the previous four-year period leading to the 2018 World Cup.

He said FIFA expected revenues to increase to $11 billion in the years leading to the 2026 tournament, which will expand from 32 to 48 teams. The 2026 tournament is being jointly hosted by the United States, Canada and Mexico.

"We are bullish about the power of football," Infantino said. "We are convinced the impact of the game will be massive.... It has been massive here and it will be incredible in North America."