[2] A prolific writer, he produced an important, scholarly study on the Three Secrets of Fatima in French (later translated into English).

[3] After his predictions of epochal events in the years preceding the turn of the millennium failed to materialise, including a catastrophic global conflict, Abbé de Nantes' movement known as CRC (contre-réforme catholique) was renamed Ligue de la contre-réforme catholique au XXIe siècle.

Because of his controversial views, the Roman Catholic Church subjected him to canonical sanctions forbidding him to celebrate Mass and the other sacraments in 1966.

The Congregation for the Doctrine of the Faith issued a notification on 10 August 1969 stating that Abbé Georges de Nantes had continued to maintain his views on the council, the aggiornamento of the Church, the French episcopate, and the so-called "heresies" of Pope Paul VI and had thereby "disqualified the entirety of his writings and his activities".

[5] The Congregation of the Doctrine of the Faith issued another notification published in L'Osservatore Romano of 16–17 May 1983, stating that de Nantes had come to Rome to present a "Book of Accusation against Pope John Paul II for Heresy, Schism and Scandal" and that the Secretary of the Congregation had received him, as instructed by the Pope, but had refused to accept from him a book that contained unjustified gravely offensive accusations of the same character as those that de Nantes had directed against Pope Paul VI in a book published in 1973.