There is an oversight in the French translation of Citadel that implies that the reaction cards which play themselves out-of-turn (Black cat, sheepdog, etc.) are subject to the effects of Citadel on another player's turn.
Current wording:
"À chaque tour, la première fois que vous jouez une carte Action, rejouez-la ensuite."
(Each turn [even other players], the first time that you play an Action card, play it again.)
Suggested wording:
"À chacun de vos tours, la première fois que vous jouez une carte Action, rejouez-la ensuite."
(On each of your turns, the first time that you play an Action card, play it again.)
Thanks, I'll forward this to our French translator.