Catechism of the Catholic Church §1883 — excerpt
Socialization also presents dangers. Excessive intervention by the state can threaten personal freedom and initiative. the teaching of the Church has elaborated the principle of subsidiarity, according to which "a community of a higher order should not interfere in the internal life of a community…
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.
Also cites: CA 48 # 4 · Pius XI, Quadragesimo anno I, 184-186