French authorities have shut down around 20 mosques and prayer halls considered to be preaching radical Islam since December, Interior Minister Bernard Cazeneuve said on Monday.

"There is no place ... in France for those who call for and incite hatred in prayer halls or in mosques, and who don't respect certain republican principles, notably equality between men and women," the minister said.

"That is why I took the decision a few months ago to close mosques through the state of emergency, legal measures or administrative measures. About 20 mosques have been closed, and there will be others."

Cazeneuve was speaking after a meeting with leaders of the French Council of the Muslim Religion.

There are some 2,500 mosques and prayer halls in France, about 120 of which are considered to be preaching radical Salafism, a strict Sunni interpretation of Islam.

He said that since 2012, 80 people had been expelled from France, and dozens more expulsions were under way, without giving further details.

The meeting comes as France struggles with an unprecedented extremist threat that has seen a raft of terror attacks, most recently a truck massacre in Nice which killed 84, and the murder of a Catholic priest in the Normandy village of Saint-Etienne-du-Rouvray.

The repeat attacks have raised tough questions about security failures, but also about the foreign funding of many mosques.

Prime Minister Manuel Valls said last week that he would consider a temporary ban on foreign financing of mosques, urging a "new model" for relations with Islam.

Cazeneuve confirmed that authorities were working on a French foundation for Islam which would guarantee total transparency in financing of mosques "with rigorous respect for secular principles."