The Pope has been in France, being given the red-carpet treatment during a three-day state visit that took him from Paris to Lourdes. The Pope was visiting "the eldest daughter of the Catholic Church", as France is known to the Vatican. It is quite an event when a pope so attached to the traditionalist wing of the Church meets a French president so little attached to the principle of secularism.

In December last year, when Nicolas Sarkozy visited the Pope at the Vatican (flanked by Carla Bruni's mother, his putative future mother-in-law, and Jean-Marie Bigard, a stand-up comedian better known in France for his salacious jokes and his denial of the 9/11 bombings than for his piety), the president seized the opportunity to develop a new idea that he called "positive secularism".

This past week, in Paris, Sarkozy did it again: advocating, in front of the evidently delighted Pope, the benefits of a secularism "more open to religions". In his speech, Benedict XVI blessed Sarkozy's idea, making himself an actor in the current French debate. Concerning the relations between the French state and the Church, he declared: "I pay tribute to your expression of positive secularism. Indeed, there still remain many open areas of discussion which we must deal with and resolve with determination and patience. I'm convinced that we need to reflect on the true meaning and importance of secularism anew."

Last year, while the French were still getting to grips with their new president, his first call for positive secularism was cautiously welcomed by the majority. With the second, many are wondering aloud: "Since when was the secularism born of the Revolution negative?"

To speak of positive secularism is to imply that there are two kinds of secularism, one good, the other bad. The supposedly good one, put forward by the Pope and his acolyte Nicolas Sar kozy, is a secularism that would allow politics to mingle with religions. One which would, for instance, turn a blind eye to sects and their actions, one which would accept that people be treated differently according to their faiths, one which would blur the frontiers between the public and private spheres. Sarkozy certainly knows a great deal about the blurring of the two distinct worlds whose separation has been France's trademark for at least two centuries.

Positive secularism would thus emerge to correct secularism as France has always known it, which the French must apparently now think of as negative: too rigorous, too restrictive, too extreme, a secularism that forces assimilation of a heterogeneous population rather than trying to create a tapestry rich with difference.

What the Pope and president pretend not to know is that there is no positive or negative secularism (laïcité in French). Secularism is neutral. It is neither a dogma nor a doctrine. If anything, it's an abstention. Secularism abstains from fav ouring one religion over another, or favouring atheism over religious belief. It is a political principle that aims at guaranteeing the largest possible coexistence of various freedoms.

From a strictly legal perspective, secularism is extremely positive: it creates a universal freedom to believe or not to believe, and protects individuals from any public interference in their belief, provided that their belief or lack of it does not disturb the peace. As the philosopher Catherine Kintzler wrote in the French weekly Marianne: unlike religion, secularism creates freedom. What religion has ever recognised the rights to believe and not to believe? What religion has promoted the physical emancipation of women? What religion accepts what believers would deem to be blasphemous words?

Instead of speaking of positive secularism, President Sarkozy would have done better to demand in the name of secularism that religions such as Catholicism be less exclusive in their political, intellectual and legal views - or, in other words, more positive.

According to the political scientist Caroline Fourest, author of a recent book on the Catholic Church, the sympathy between the Pope and the French president shouldn't be surprising. Their "new idea" is a Trojan horse. The term "positive secularism" was actually coined in 2005 by the then Cardinal Ratzinger, whose views have inspired two of President Sarkozy's close aides and speechwriters, the practising Catholic Emmanuelle Mignon and the Dominican friar Philippe Verdin.

So what we have witnessed is Nicolas Sarkozy pretending to have an idea that originated at the Vatican, while the Pope, its delighted author, sits back and waits for the president to implement "his" idea. A few days ago, in an interview with the Catholic French daily La Croix, Benedict's private secretary clearly stated that the Holy Father expected the president of France to diligently transform this idea into acts. Machiavelli would be impressed.