If both play well they might still be fighting for places for Hanover at next week's Stockholm Open, where they are due to be seeded second and fourth.
Henman had looked certain to be in the eight-man Hanover field until the Dutchman, Richard Krajicek, won the Stuttgart tournament on Sunday.
Rusedski is back in 13th place and seemingly out of contention for the ATP finals but there are so many points at stake in Paris that if he won this week and then did well at Stockholm he would be back in contention.
Having received a first-round bye, Rusedski, who is seeded No 13, is due to start his Paris campaign against Nicolas Kiefer, while Henman, who also has a first-round bye, will meet the winner of the match between the Australian, Richard Fromberg, and the French wild card, Arnaud Di Pasquale.
Yesterday Thomas Enqvist, the 1996 winner of the Paris event and the current world No 21, was beaten in the first round, 6-3, 6-3, by the Italian qualifier, Gianluca Pozzi.
The Swede's defeat was hardly surprising because he had not played a competitive match since he withdrew with an injury from the Czech Indoor tournament last month.
Steffi Graf's latest comeback began yesterday with the former world No 1 losing a doubles match at the Leipzig Open.
The German, badly affected by injuries for the past two years, appeared relaxed playing for the first time in 56 days following an operation on her right hand after the US Open. She chose to play with the 16-year- old, Mia Buric, the pair losing to Arantxa Sanchez-Vicario and Natasha Zvereva 7-5, 6-4.
"Physically I feel good," Graf said. "But since we were playing one of the world's top doubles team, we approached the match in a pretty easy- going way."
The 29-year-old steps on the court today for her first comeback singles match, against the Romanian, Ruxanda Dragomir, earlier than anticipated. She had planned to return next week at the Philadelphia event.
She took a wild card at Leipzig, a tournament which she helped found and won every year between 1990 and 1993, because her latest injury had healed faster than expected.