The sisters are in the same half of the draw, so only one can reach the final.
Kim Clijsters was in Serena's half of the draw, while Jennifer Capriati was in the same half as Venus.
The sisters are in the same half of the draw, along with Capriati, who showed signs of life by reaching the final in Rome earlier this month.
The answer was the top half, which means Federer, seeded 3rd this year, is in the same half as the top-seeded Novak Djokovic.
Nadal will open his latest title defense against Simone Bolelli of Italy and is in the same half of the draw with Andy Murray, the 4th seed.
Top-seeded Gustavo Kuerten -- a clay-court specialist with the talent to win on the hard courts -- is in the same half of the draw as fourth-seeded Lleyton Hewitt and Andy Roddick.
Ireland's victory over Australia in Pool C has made it likely that all of the Tri-Nations sides will be in the same half of the draw for the knockout phase.
On the women's side, the heavy favorite, third-seeded Serena Williams, is in the same half of the draw as top-seeded Victoria Azarenka, leaving No. 2 Maria Sharapova with a less daunting possible semifinal match against No. 4 Agnieszka Radwanska.
It cannot be two because last year's finalist Ana Ivanovic, the No 2 seed, is in the same half as Jelena Jankovic, who has arrived in Paris with the confidence of a morale-boosting win in Rome only a week ago.
They are in the same half of the draw, and the fifth-seeded Roddick is in the tougher section, with Novak Djokovic and the resurgent Lleyton Hewitt in his quarter.
