If this will be the truth I think PSG will have a very low chance to beat Manchester City with a useful result.
Remember they need to win with 2 goals advantage in England not an easy task without their best player.
I hope it doesn't turn out to be true. If it is, then it would be unfortunate for Pochettino's men. City knows that they are in a very good position to win the tie and would do everything in their power to see that happen. PSG would need a fast paced player like Mbappe to break through city's defense. I wouldn't say PSG wouldn't stand a chance without their key players, only that it would a difficult task to achieve. I remember some years back when key players for Liverpool like Salah was injured just before leg against Barcelona. We still made it through. PSG shouldn't be written off just yet.