Steady erosion of church-state separation in France today
Napoleon's concordat is not a dead. It lives on the fringes, poised to be extended throughout France whenever the political conditions allow. The Church has been urging the extension of the Napoleonic Concordat beyond Alsace-Moselle, quietly concluding concordats under other names, gradually acquiring state subsidies and even offering pilgrimage tourism to particularly pious regions.
In four French Departments Napoleon's Concordat remains essentially unchanged. Three of these are in mainland France. These are Upper Rhine and Lower Rhine (all of Alsace) and Moselle (the north-eastern part of Lorraine). At the time when France cancelled the Concordat, these were under German rule and so were not affected. When these territories returned to France, they brought the Napoleonic Concordat back with them.
In Alsace-Moselle the Concordat, which once applied only to the Catholic Church, has now been extended to the Protestant and Jewish denominations, and, although the Muslims are not (yet) included, the new Mosque in Strasbourg is being subsidised by the state “like a Concordat house of worship”.  Over the years various changes have been made to the Napoleonic Concordat. Some of them are formal, such as replacing the words “First Consul” with “Minister of the Interior”. Others do away with some of the controls put in place by Napoleon, such as his Article 10 which limits the bishops’ ordination of priests to “to those persons agreeable to the Government”.  However, in general the changes are minor enough that it has been called “the grooming of the Concordat” (toilettage du concordat). Napoleon’s Concordat lives on.
And it also persists, here and there, in a fourth administrative area, as well. This is the Overseas Department which stretches around the globe. France’s far-flung territories find themselves living under a patchwork of the 1905 Separation Law (or its 1939 version, the Décrets Mandel), the decrees of Charles X and Napoleon's Concordat. 
However, even remnants of the Napoleonic Concordat represent a foot in the door. A concordat on the fringes functions a bit like the unofficial modus vivendi with Communist nations, during the Cold War: it secures whatever privileges can be got now, while serving as a precedent for a future concordat.
A number of developments are now taking place which could prepare the way for a new concordat. The Church has been claiming that concordats express French civic values, while at the same time urging the extension of the Napoleonic concordat beyond Alsace-Moselle, updating a seemingly trivial concordat with the French Government, gradually acquiring state subsidies and offering pious regions new pilgrimage tourism.
♦ Redefinition of "concordats" and "secularism"
Any revival of the concordat in secularist France would require quite a shift in public opinion. Therefore, where the Vatican can't hide a concordat under a name like "endorsement of a diplomatic convention" they must try to improve its public image by redefining it. Hence the remarkable assertion by the Archbishop of Strasbourg that "the concordat is an effective and positive implementation of a true secularism."  Complementary to this is the redefinition of "secularism" by President Nicolas Sarkozy. He advocates what he calls "positive secularism", which turns out to involve state subsidies to religious groups: exactly what "normal" secularism is supposed to prevent.
♦ Under-the-radar infringements
A further strategy for bringing back the concordat was outlined by the Vatican’s nuncio (ambassador) to France. In 1996 he demanded "the extension of the statute of Alsace-Moselle [Napoleon’s Concordat] to the whole group of French regions that have a strong spiritual density".  From its toehold in Alsace-Moselle, the Concordat is to be reintroduced bit by bit, beginning in other pious corners of the country. They’ve already started in remote regions by erecting crosses on mountain peaks  in defiance of the Separation Law whose Article 28 forbids putting up a religious symbol in any public place.  Nevertheless, the Diocese of Gap in the French Alps has published pictures of the cross on the summit of the Charance, re-erected on what looks like a Church youth group outing after it was unfortunately struck by lightning. 
♦ Trivial concordats as "precedent"
Within Alsace-Moselle, where there is already a concordat for the whole Department, in 1974 a minor, but still precedent-setting "Convention" was concluded. This related to the "Independent Centre for Formation and Religious Pedagogy" at the University of Metz.
Another foot in the door is obtained by the periodic updating of a concordat about a church and convent in Rome which were, until recently, run by French nuns. The Concordat for the Trinity of the Mountains, concluded with Charles X in 1828, has been carefully renewed in 1974, 1999 and 2005. The 1999 version claims that this concordat is meant to support “secular expression” by, of all people, nuns of the Society of the Sacred Heart of Jesus, who were said to be working for “the teaching of the language and the diffusion of French culture”. Trivial as this concordat may seem, it could have future significance since, unlike the remnants of Napoleon’s Concordat which only involves some French Departments, this one which regulates the “secular mission” of the Catholic order in Rome theoretically concerns the whole of France. Someday that could set a precedent. (More about this strange concordat here.)
♦ State subsidies
As soon as enough piecemeal financial privileges have been granted to the Church, it becomes easier to argue that a concordat is a pure formality which just puts them all in order. These state subsidies can be delivered directly through grants, indirectly through tax breaks or even, in a very roundabout fashion, through laws permitting bequests to Church institutions. Direct grants now include subsidies for Church-run schools, pro-life associations, the priests' healthcare system and, thanks to Marshal Pétain, public maintenance of Church property. Tax exemption was introduced in 1966 by the Martinière Circular which lets religious associations run untaxed commercial enterprises.
And another very profitable source of income was given to the Church in 1942 by Marshal Pétain when he permitted Church institutions to accept bequests. (This makes it easier for vulnerable residents to be pressured into leaving their money to the Church-run institutions where they live, a situation which in Germany, this had to be legally forbidden.) And finally, in the corner of France still under the Concordat, subsidies to the Church are even more generous. In Alsace, for example, the Roman Catholic bishop is paid by the state € 4,485, whilst each Catholic priest receives € 2,704. 
♦ The pilgrimage business
There is now a new and mutually profitable way for the Vatican to strengthen the influence of those corners of France with "a strong spiritual density". This can be done by creating an international shrine there and then flying in pilgrims on the new Vatican airline. (The Church calls this "the quest to find God on exclusively low-cost flights".) One of these regions is Lourdes in the French Pyrenees and it was to Lourdes that the Vatican airline transported its very first group of pilgrims in 2007. For that year the Church claims a loss: Francis Dehaine who manages the Lourdes sanctuary said there was a shortfall of 58,000 Euros after expenses, including renovations to the pilgrim hotels and the 22 churches and chapels.  However, these claims of poverty contrast with the results of an investigation initiated by Tracfin, the money-laundering detection unit of the French finance department. In 2008 they noticed that the shrine's rector, Raymond Zambelli, whose income was officially estimated at 8700 Euros had stashed away 427,000 Euros in his personal bank account..... 
Another alpine pocket of piety is Gap in the French Alps. In 2008 Gap finally managed to obtain Church certification for some 2500 apparitions seen by a local shepherdess.  (One wonders how much attention she was able to devote to her sheep.) As mentioned above, the parishioners at Gap have long defied French secularism. Now, with their place in the sacred tourist sector well assured, they look set to get their earthly reward.
The erosion of a value as central to France as secularism must proceed slowly. However, the Church is patient: the Vatican thinks in centuries, and a concordat for the whole of France remains on its agenda. In secular France a new concordat will take time, but the Church is waiting at the door. 
Robert Todd Carroll, “Lourdes”, Skeptic's Dictionary, 2008.
“Separation of church and state”, 5.3 France, Wikipedia.
“1905 French law on the separation of Church and State”, Wikipedia.
1. Steven Erlanger, “Strasbourg Journal: A Pro-Church Law Helps a Mosque”, New York Times, 6 October 2008. http://www.nytimes.com/2008/10/07/world/europe/07alsace.html?ei=5070&emc=eta1
2.The revisions of 10 January 2001, « Décret no 2001-31 du 10 janvier 2001 relatif au régime des cultes catholique, protestants et israélite dans les départements du Bas-Rhin, du Haut-Rhin et de la Moselle », can be found in French online. http://lp44.free.fr/modules.php?name=News&file=article&sid=11
For a good summary, see: José Arias et Paul Klein, "Le statut clérical d’exception d’Alsace-Moselle", Juin 2007. http://librepenseefrance.ouvaton.org/spip.php?article39
3. La ligue de l'enseignement, "La situation outre-mer". http://ww1.laicite-laligue.org/index.php?option=com_docman&task=doc_download&gid=288
4. "Le concordat est une mise en oeuvre effective et positive d'une vraie laïcité". Quoted in Jacques Fortier, Religion page, “Dernieres nouvelles d'Alsace”, 12 September 2001. http://lp44.free.fr/modules.php?name=News&file=article&sid=11
5. "L'extension du statut d'Alsace Moselle à l'ensemble des régions françaises à forte densité spirituelle." Quoted in “Lettre ouverte aux candidats à l'élection présidentielle”, adopted by the Colloque de Strasbourg, 8 December 2001. http://librepenseefrance.ouvaton.org/actions/coll_stras_bourg.htm
6. Three are listed, (Aurouze, Gap-Charance, and Pic deBure). http://laicite.free.fr/picbure.htm
See also a brief article by the Union des Familles Laïques du Finistère, 13 September 2006.
7. Law concerning the Separation of the Churches and the State, Article 28: “It is forbidden, in the future, to erect or to put up any religious sign or symbol on public buildings or in any public place, except on buildings used as places of worship, on burial grounds in cemeteries, on funeral monuments and on museums or exhibition halls.” http://www.concordatwatch.eu/showkb.php?org_id=867&kb_header_id=849&order=kb_rank%20ASC&kb_id=1525
8. Weblog of the Diocese of Gap in the High Alps http://diocesedegap.over-blog.com/photo-226835-dscn0858_jpg.html
9. Appeal of the Estates General for Secularism at the initiative of the Libre Pensée, 9 December 2006 at Paris. http://www.iheu.org/node/2475
10. Law no. 1114 of 25 December 1942 modifying the law of 9 December 1905 concerning the separation of the churches and the State, Article 1.
11. Libre Pensée, ibid.
12. Gesche Wüpper, "Das Finanzwunder von Lourdes", Die Welt, 15 September 2008.
13. Jason Burke, "Lourdes fears priestly scandal will make profits dry up", The Observer, 13 July 2008. http://www.guardian.co.uk/world/2008/jul/13/catholicism.france
14. Henry Samuel, "New French shrine 'could rival Lourdes'", Telegraph, 5 May 2008. http://www.telegraph.co.uk/news/worldnews/europe/france/1927473/New-French-shrine-'could-rival-Lourdes'.html
15. "On 12 February 2002 at the Hôtel Matignon the Prime Minister met the president of the Bishops' Conference of France, the Archbishop of Paris, a delegation led by the apostolic nuncio, the ambassador of the Vatican.[!] Together they formed a 'permanent structure for dialogue and consulation with a view to undertaking an examination of the problems posed by the relations between the Catholic Church and the State'. [...] This government decision to grant the principle of clerical claims, to know the offical position of the churches as institutional partners of the State, constitutes a major violation of one of the fundamental laws of the Republic. This means the return of the Concordat."
Press release of Libre Pensée, "Après la rencontre entre le Premier Ministre et l'Eglise catholique : Non au retour du Concordat!" 25 March 2002. http://librepenseefrance.ouvaton.org/actions/com_presse_25_03_2002.htm
Last update 20 May 2010