Police have shut down makeshift Muslim prayer rooms at Paris' two main airports after they came under scrutiny following a far-right politician's allegations that Islamists were compromising security.

Officials insist there was no threat. But the prayer sites set up by Muslim workers in cloak rooms, depots and other areas at Charles de Gaulle and Orly airports were quietly shuttered. There are three official prayer rooms still open at each airport, just as there are chapels for Christians and synagogues for Jews.

A book published in May by Philippe de Villiers, a presidential hopeful who opposes Muslim immigration, said clandestine prayer rooms honeycombed the corridors beneath airport runways and that Muslims were poised to put the premises under Islamic Sharia law.

CountryWatch: France

Villiers claimed to base his book, "The Mosques of Roissy," on intelligence reports. While many saw the book as a publicity grab, it caused a stir and briefly climbed the best seller list.

After excerpts were published, Interior Minister Nicolas Sarkozy, considered the leading conservative presidential candidate, visited Charles de Gaulle airport in April and insisted measures were under way to strengthen security.

Officials have insisted the unofficial prayer sites posed no risk and said employees in sensitive areas are carefully vetted.

Eight prayer rooms were shut down at Orly airport, said Yvon Caratero, deputy chief of the Air and Frontier Police for Orly, calling it a "precautionary" measure.

"It was a problem that really wasn't one. ... There were no meetings to talk about Islam. There was no imam preaching. It didn't present a particular risk," Caratero said.

The daily Le Parisien reported last week that some 30 prayer rooms were shut at de Gaulle.

Hazem El-Shaffei, the imam for both airports, confirmed unofficial prayer rooms were shut at de Gaulle but did not say how many. He said by telephone that he was not opposed to shutting them, but he stressed the prayer rooms were "not a question of any threat."

The airports are major employers on the north and south edges of Paris where numerous Muslims live and work.