Football World Cup: France hit by injury scare on eve of final, striker Olivier Giroud reportedly battling knee injury

France's hopes of defending the Football World Cup appear to have been dealt a serious blow, with striker Olivier Giroud reportedly in doubt with a knee injury.

According to local reports, Giroud is racing to prove his fitness to play in the World Cup final, when 'Les Bleus' face Argentina on Monday morning (NZ time).

Giroud, 36, is understood to have sat out parts of France's late training runs, with L'Equipe reporting Marcus Thuram - son of World Cup-winning defender Lillian - playing in his place.

So far, Giroud has scored four goals at the World Cup, with only teammate Kylian Mbappe and Argentina talisman Lionel Messi (five) scoring more.

The loss of Giroud would be another blow for France's forward stocks, after also losing reigning Ballon d'Or winner Karim Benzema to a thigh injury on the eve of the tournament.

Benzema has since returned to fitness, but coach Didier Deschamps is reluctant to comment on whether he will be recalled into the squad.

Because France never replaced him, Benzema would be permitted to rejoin his teammates under FIFA regulations.

As well as an injury in their forward line, France have also battled an illness outbreak in camp, with players struck down by colds before and after their semi-final victory over Morocco.

France aim to become the first team in 60 years to defend the Football World Cup title, with Brazil (1958 and 1962) the last side to do so.