Catechism of the Catholic Church §2488 — excerpt
The right to the communication of the truth is not unconditional. Everyone must conform his life to the Gospel precept of fraternal love. This requires us in concrete situations to judge whether or not it is appropriate to reveal the truth to someone who asks for it.
This translation is under copyright, so only the cited words are quoted here. Follow the link for the full text. Translation: English translation of the Catechism of the Catholic Church, 2nd ed. (Libreria Editrice Vaticana), as posted at vatican.va.