"I won't be participating -- not because I don't agree with the demonstration, but because I don't think I need to march when I have to make something known to the government and president," Cardinal Andre Vingt-Trois, president of the bishops' conference, told France's Le Figaro daily.

"But I've invited Catholics and everyone else with something to say on this matter to demonstrate," he added. "We're not under a dictatorship."

A coalition of 30 French family groups, "Manif Pour Tous" (Demo For All), plans a Jan. 13 Paris rally against a bill allowing same-sex marriage, introduced Nov. 7 by the Socialist government of President Francois Hollande under the slogan, "Marriage for All."

In a Jan. 2 report, the Catholic La Croix daily said 4.5 million leaflets had been printed for the Jan. 13 rally, converging on the capital's Champ de Mars, and special trains would be provided by organizers.

The Paris archdiocesan website said a "prayer vigil for marriage and the family" would be held at the city's St. Nicholas Church before the event, during which Catholic groups would be providing help.

It also published a draft letter for protesters to send to local mayors and legislators.

Meanwhile, other church leaders also urged Catholics to take part, including Bishop Andre Marceau of Perpignan-Elne, who welcomed the transportation help being offered by Catholic family associations in his diocese in southern France, along the Spanish border.

Hollande pledged to introduce the legislation during the spring presidential campaign. The bill, allowing gay and lesbian couples to marry and adopt children, has been opposed by Catholic bishops. About two-thirds of France's 60 million inhabitants profess Catholicism.

Earlier mass protests against the measure, which is also opposed by other Christian denominations, Muslims and Jews, were staged during October and November.