(9/14) The Pope has instructed Vatican officials to adopt stricter criteria for the approval of visions of Mary.

As Pope Benedict XVI began his first visit as pontiff to France, being greeted at Paris airport by President Sarkozy and his wife Carla Bruni, it emerged that he had asked a Spanish Jesuit to draw up new guidelines for bishops around the world on the recognition of reported apparitions.

The Vatican said it had asked Monsignor Luis Francisco Ladaria Ferrer to launch his investigation because the Pope wanted to avoid "excesses and abuses" of such visions. The pontiff believes bishops should resist being swayed by the emotional reaction of believers and be guided instead by strictly applied "scientific, psychological and theological criteria".

Ignazio Ingrao, Vatican correspondent of the weekly news magazine Panorama, said the inquiry had been prompted because of the readiness of a bishop of Civitavecchia, the port north of Rome, to approve reports that a statue of the Madonna owned by a local family had wept tears of blood. The bishop even claimed to have seen the tears himself while holding the statue in his arms. The bishop was later replaced.

The Vatican is also sceptical about reported Marian apparitions since 1981 at Medjugorge in Bosnia-Herzegovina, despite the fact that the site is visited by two million pilgrims a year.

Vittorio Messori, an Italian Catholic writer who is close to the Pope, said the then Cardinal Ratzinger had told him in 1985 that "patrience and caution" were the key to validating Marian visions. "No apparition is indispensable to the faith" the future Pope told Messori. "The Revelation ended with Jesus Christ".

Guidelines for the approval of apparitions and revelations were last issued in 1978. They lay down that a diocesan bishop can "either on his own initiative or at the request of the faithful" choose to investigate an alleged apparition. He then submits a report to the Vatican for approval.

The news came as the Pope visited France and prepared to hold talks with Mr Sarkozy as well as visiting a religious shrine at Lourdes. France is overwhelmingly Roman Catholic - at least nominally - but also has large Muslim and Jewish communities and adheres to the separation of church and state. Mr Sarkozy is himself a lapsed Catholic who has been divorced twice. While in the country, Benedict is to deliver a keynote address on the role of religion in society to the French Academy, of which he has been a member since 1992.

Before leaving Rome on his trip, Benedict, who speaks fluent French, said he would pray at the feet of Our Lady of Lourdes for the Church, the "sick and abandoned", and peace in the world.

"I go as a messenger of peace and fraternity," he said in a message to the French people. "Your country is not unknown to me. On several occasions I have had the joy to visit it and to appreciate its generous tradition of hospitality and tolerance, as well as the solidity of its Christian faith and its lofty human and spiritual culture."

He added: "May Mary be for all of you, and in particular for young people, a Mother always attentive to the needs of her children, a light of hope that illuminates and guides your ways."