All three are struggling to prove their fitness for the first leg of the tie in the French capital next Wednesday with midfielder Toure the latest addition to the injury list.
The 32-year-old, troubled by a heel injury in recent weeks, now has a knee problem and will definitely miss Saturday's Barclays Premier League trip to Bournemouth
Goalkeeper Hart suffered a calf injury in the derby loss to Manchester United a fortnight ago while captain Kompany remains on the sidelines with a similar problem.
Manager Manuel Pellegrini said: "For the three of them it is difficult. They are working. I am not 100% sure but I think it will be difficult for them to play on Wednesday.
"Yaya has a problem in his knee and he was playing in the last game with some trouble."
On the positive side for City, midfielders Kevin De Bruyne and Samir Nasri are both fit and back in contention for the game at Bournemouth.
De Bruyne has been out since suffering knee ligament damage and a sprained ankle in January while Nasri has not played since the visit of the Cherries last October after undergoing thigh muscle surgery.
Pellegrini said: "It is two months that Kevin couldn't play but I saw him work this week without any problems.
"The same for Samir Nasri. He had a very long injury, very unexpected. Now he has the last part of the season to demonstrate how good a player he is.
"I hope both of them will be very important. Especially at the end of the season, it is important to have fresh players and good players."
Pellegrini says he will have no qualms about picking defender Martin Demichelis, who was charged by the Football Association this week over alleged betting offences.
"I spoke with Martin," Pellegrini said. "He told me what he did. We must see what the FA determines about that. We must wait for next week.
"Martin is part of the squad. He is always very committed to this project. If he has made a mistake we will see how important it is but I don't think it will be a very serious mistake."
Source: PA