I think you are wrong.
We get beat in Paris and they beat Red Star.
What if we beat them 2-1 at home? Both on 9 points and then it goes to head to head.
Dont they go through on away goals? 1-0 at their place and 2-1 at ours. So we would have to beat them either 1-0 to force extra time, or by 2 goals.
Or does it go on Goal Diff after the head to head (we beat them 1-0 so both results between us and Napoli the same) ? In which case, with us beat in Paris and they beat Red Star, our GD would be worse, and we would have to beat them by two goals anyway to win on the head to head.