Marcoussis - France captain Thierry Dusautoir believes this could be his last Six Nations tournament.
The Toulouse flanker will lead his country out against Scotland at the Stade de France on Saturday knowing that this year could be his last as a member of Les Bleus.
The 33-year-old expects to captain his side at the World Cup in England towards the end of the year, but after that, he's not sure he'll be involved any more.
"I don't think like that because many things can happen," he said when asked if this would be his last Six Nations.
"I'm closer to the end than to the beginning, that's for sure.
"If I'm called up for a match during the 2016 Six Nations I don't know if I would have the courage to refuse it.
"But I'll be 34 then, maybe the coaching staff at the time will want to use younger players because it's certain that I won't be going to the World Cup in Japan in 2019.
"Today (Friday) I'm on the eve of a match against Scotland. Even though there's a strong chance that this is my last Six Nations, the priority in my mind is that match.
"It's not about deciding when to retire from the international scene."
Although this is a World Cup year, Dusautoir said the best way to prepare for that event, or to earn a place in the France squad, is to focus on winning the Six Nations.
"We're concentrated, vigilant. There's a lot of enthusiasm. We want to begin this tough Six Nations well.
"We've seen for some time now that there are no small teams like there were 10 years ago.
"We need to try to build confidence, also for the upcoming matches.
"The Six Nations will be a great test because we have three matches away from home -- in Ireland, England and Italy, where we've lost the last two.
"We've got some work to do. The World Cup is both close and far away in our minds.
"We know it's the last international appointment before the World Cup squad will be announced.
"But the best way to prepare for it (the World Cup) is to focus on the Six Nations."