Defending champions PSG are top of Ligue 1 with 54 points from 23 games, five points ahead of fellow big-spenders Monaco.
Ranieri has kept playing down his team's chances of fighting for the title this season and on Friday repeated that PSG were from a different planet.
"You have to tell the truth, there is a great difference of level between PSG and us," he told a news conference. "They are extra-terrestrial, I repeat it.
"But it's very good because it will allow me to see how my players behave in a game that looks like a Champions League match, and it's a competition we want to play next season."
He hopes his players will be capable of posing a challenge on Sunday, having managed a 1-1 draw at the Parc des Princes earlier in the season.
"Them being extra-terrestrial doesn't stop us from wanting to fight. I'm a competitor, as are the players. I'm ambitious and I always want to win, even if we'll need to give 120 percent to match their level," he said.
Last weekend, Ranieri had said after his side's 2-2 draw at Lorient that PSG were so strong that they had won the title even before the league had begun.
PSG midfielder Blaise Matuidi smiled when he was asked for a comment on Friday.
"He made many people laugh. It's the big bluff," the France midfielder told reporters.
"I had the chance to know him as a coach and I know that he's a really clever one," Blanc said.
Blanc expects to have his full squad available for the game while Ranieri could hand striker Dimitar Berbatov his first start since he joined Monaco from Fulham last month to cover for Radamel Falcao's long-term injury absence.
"I think Berbatov will be able to play and even start," Ranieri said. "He can bring us his experience as a great champion, his calm and his ability to understand the game."