Marshal Pétain’s marriage of convenience with the Church
The Church lent much-needed support to the French head of state, Marshal Philippe Pétain, whose German puppet regime was run from Vichy. In return, Pétain granted the Church privileges which have undermined French secularism.
("Un petit service en vaut un autre.")
Although there were individual French clerics who supported the Resistance to the Nazis (just as there were a few aristocrats who supported the French Revolution), the Church as a whole backed the German puppet regime of Marshal Pétain. For one thing, they shared the common values of authoritarianism and corporatism. For another, they also shared the same enemies. However, the main reason for the collaboration between Pétain and the Church was a simple bargain: the Church lent support to the Fascist Pétain and in return, he granted the Church privileges. Although the Vatican didn’t succeed in getting a concordat, this collaboration seriously undermined the 1905 law which had strictly separated church and state. Here’s how the bargain worked.
Part 1 : Church support for Pétain
Extract from Hansi Brémond 
Even well before Hitler took power in Germany, French Catholics admired Fascism, without themselves being Fascists; they recognised a number of advantages, such as the elimination of their enemies. In fact, a poster of 1926 by the Catholic Republican Union asserts : "We are one society and Fascism is another ; but if Fascism makes you disappear, oh free thinkers, humanity will be well rid of you…!"
In 1933 the very Catholic journal, La Croix (The Cross), expressed satisfaction that "the German concordat of 20 July is the most important religious event since the Reformation" ; The Cross "rejoices that the new German education regulations require the complete exclusion of secularism from the school". […]In 1940 France lost to the Germans and a regime of collaboration was set up, with Marshal Pétain at its head. This regime ordered the French to no longer consider the Germans as enemies and to lay down their arms. To appear legitimate in the eyes of the population, this government, said to be from "Vichy", needed the support of the Catholic Church. It obtained this support right away and without restrictions ; the Catholics propped up this regime which drew inspiration from the social doctrine of the Church and which wanted to purge France of Jews, Communists, Socialists, freemasons, free thinkers, atheists… all those who were blamed for the French defeat .
Part 2 : Pétain’s concessions to the Church
30 July 1940: Archbishop Salieges states: "The legitimate government of France is headed by a man who has given France the gift of his person. A magnificent example of the renunciation of all egotism and of a noble love of the fatherland".
2 October 1940: The Archbishop of Aix announces: "Without hesitation we should all group ourselves around the the illustrious Marshal".
2 October 1940: In La croix one is informed that: "The teachings of the Head of State are similar to those of the Sovereign Pontiff".
19 November 1940: Cardinal Baudrillart, Rector of the Catholic University of Paris, declares: "In the skies over France in 1940, skies full of tempests, a beneficial light has been manifested and has revived all our hopes! This light is, of course, the Marshal".
16 February 1941: Bishop Dutoit of Arras calls to mind the duties of a good Catholic: "The duty is simple, yet of utmost gravity: to follow, and support with our confidence, Marshal Pétain".
3 December 1941: Archbishop Baudrillart writes: "Against the powers of the demons, Archangel Gabriel wields his avenging sword, shining and invisible. With him march the Christian and civilised peoples who defend their Fatherland, their future, beside the German armies".
1942: The Bishop of Marseille states: "We are not ignoring the fact that the Jewish question poses difficult problems, nationally and internationally. We well recognise that our country has the right ot take all necessary measures to defend us against those who, especially in recent years, have done it so much harm, and that it has the duty to severly punish those who abuse the hospitality which is so liberally accorded them".
28 January 1942: Pope Pius XII extends his blessing to the journal La Croix and describes it as: "an organ of pontifical thought". […]
February 1942: Bishop Lusaunier, Director of the seminary of the Carmelites, states: "The French should obey Pétain, not De Gaulle".
May 1942: In the brochure, Frenchmen! Your bishops address you, one can read: "In the social and civic domain we profess complete loyalty to the power established by the Government of France, and we urge our faithful to enter into this spirit."
February 1944: The Bishops of France condemn the Resistance army; Cardinal Gerlier states: "Pétain is France, and France is Pétain!"
Extract from Christian Eyschen 
Right from the beginning, Marshall Petain, in concert with the Catholic Church, attacked the laicité of the School and that of the State. Extraordinary legislative measures were introduced between 1940 and 1944, and their essence is still maintained on the statute books. Here is how the intentions of the 1905 law have been subverted:
15 July 1940: Cardinals write to Pétain to reintroduce teaching of religion in Public Schools.
October 1940: The prestigious Ecoles Normales, established in 1794 after the French Revolution, are abolished.
6 December 1940: The French State decides that "Duties towards God" should be taught in Public Schools.
6 January 1941: The optional teaching of religion is introduced in Public Schools.
February 1941: Religious buildings are restored to the Church by the Pétain regime, undoing the work of the 3rd Republic and the provisions of the 1905 law: amongst the properties returned are the [grottoes] of Lourdes. This remains on the statute books even after the Liberation of France - enabling the Church to once again became a real estate power.
1941: The archbishops write to Pétain, asking for a new concordat with the Vatican.
2 November 1941: A law is promulgated, allowing private Catholic schools to be subsidised by public funds. Later, public [state] school budgets are allowed to finance private schools.
8 April 1942: The July 1904 law on Congregations is abrogated and they are allowed back. Even after the Liberation of France, the 1904 law remains abrogated.
25 December 1942: Catholic cultural associations are accorded civil and testamentary rights. The 1905 law prohibited prelates from visiting and extracting donations from dying persons, but this is changed and Catholic cultural associations are now allowed to receive donations. This Pétainist law is not abrogated even after the Liberation of France. Today, when the Catholic Church receives the legacy of an adherent, it is as per the provisions of a Vichy law.
3 January 1943: A law renders communes responsible for the maintenance costs of churches. While this law was abrogated at the time of the Liberation, easy ways around it have been found [ever] since.
* Jacques Adler, “The French Churches and the Jewish Question: July 1940 - March 1941”, Australian Journal of Politics and History: Volume 46, Number 3, 2000, pp. 357-377.
1. Hansi Brémond, “L’Eglise catholique et le nazisme”, 13 November 2005. [A list of sources is given in the French original.]
2. Christian Eyschen, "How the 1905 law has been subverted: from the Vichy Regime to the Vth Republic", 13 March 2006. Translation by Babu Gogineni.
The French original is at http://ibka.org/artikel/ag03/1905fr.html
A German translation is at http://ibka.org/artikel/ag03/1905de.html