The Frenchman cannot see the Parisiens winning the return leg, but believes they will pose a huge threat to the Blues' European aspirations if they win at home
Laurent Blanc's men face Jose Mourinho's side in the first-leg of their quarter-final tie in the French capital on Wednesday ahead of the return leg at Stamford Bridge a week later.
Desailly does not think PSG have any chance of winning in west London, suggesting that Zlatan Ibrahimovic and Co. will go for the jugular in the opening game to make up for what he foresees as inevitable defeat in the latter tie.
"We are all expecting something from Paris," the Frenchman told talkSPORT. "Last year they lost the quarter-final to Barcelona. In France, every single person is expecting them to go through to at least to the semi-final to improve on last year.
"When you see the quantity and money they’ve spent, for the French league it’s amazing. The Champions League has the sweetness now; the French league doesn’t attract them anymore.
"They’ve won it two times already, they really want the Champions League, it’s going to be a tough game. All will be decided in Paris.
"If Chelsea manage to score or succeed in Paris I don’t see Paris coming back to Stamford Bridge. With the statistics Chelsea have at home, Paris can’t win."
Mourinho's men head into the tie on the back of a shock 1-0 defeat to relegation-threatened Crystal Palace, which has put their title threat in jeopardy and allowed Liverpool to overtake them at the top of the Premier League.
In France, PSG edged a 1-0 win over Nice on Friday which helped them to extend their lead at the top of Ligue 1 to 13 points with just seven games left to go.