MARSEILLE, France  The bright cafeteria of St. Mauront Catholic School is conspicuously quiet: It is Ramadan, and 80 percent of the students are Muslim. When the lunch bell rings, girls and boys stream out past the crucifixes and the large wooden cross in the corridor, heading for Muslim midday prayer.

“There is respect for our religion here,” said Nadia Oualane, 14, a student of Algerian descent who wears her hair hidden under a black head scarf. “In the public school,” she added, gesturing at nearby buildings, “I would not be allowed to wear a veil.”

In France, which has only four Muslim schools, some of the country’s 8,847 Roman Catholic schools have become refuges for Muslims seeking what an overburdened, secularist public sector often lacks: spirituality, an environment in which good manners count alongside mathematics, and higher academic standards.

No national statistics are kept, but Muslim and Catholic educators estimate that Muslim students now make up more than 10 percent of the two million students in Catholic schools. In ethnically mixed neighborhoods in Marseille and the industrial north, the proportion can be more than half.