A French ban on praying in the street came into force on Friday, driving thousands of Muslim worshippers in northern Paris into a makeshift prayer site in a disused fire brigade barracks, angering a small but vocal minority.
The street-prayer ban has highlighted France's problems assimilating its five-million-strong Muslim community, which lacks prayer space, and follows a long-running controversy, fanned by far-right leader Marine Le Pen, over Muslims forced to lay their prayer mats on the streets in big cities.
Interior Minister Claude Gueant directed Muslims in Paris to temporary spaces made available pending the building of a huge new prayer space and warned that force would be used if necessary as police end their tolerance of street prayers.
Seven months before a presidential election, the ban has struck some in France as an attempt to rally far-right sympathisers to President Nicolas Sarkozy's centre-right camp.
At the barracks, Cheik Mohammed Salah Hamza oversaw prayers for Muslims who had migrated from around the city. Worshippers streamed in, spreading their woven prayer mats over the floor of the hangar-like building and out into the courtyard.
"It's the beginning of a solution," Hamza said before the start of the service. "The faithful are very pleased to be here. The space, which holds 2,000, is full."
Many worshippers were also upbeat. "This will be better than rue Mryha," said one man, referring to a Paris street renowned for hosting street prayers. "Apparently, it shocked people."
Le Pen has described the growing phenomenon of praying on the streets and sidewalks as an "invasion".
"It's Marine Le Pen who started all this," a woman who gave her name as Assya said on her way into the former barracks on the outskirts of Paris. "Now the government has banned street prayers and sent us here so they can gather votes from the (far-right) National Front (party) -- that's all."
In France, where a strict separation of church and state has been in force for a century, public displays of religious activity are frowned upon.
Yet efforts by Sarkozy's conservative government to restrict religious displays, such as a ban on full-face veils, have drawn criticism as empty measures that unfairly single out Muslims.
France counts the largest Muslim minority of any European country. But only a portion - about 10 percent, or the same proportion as among Catholics - are practising, according to Muslim associations.
As a rule, radical Muslim voices in France are rare, but Friday's prayers in northern Paris drew a small but angry protest from a radical minority more often seen in online posts.
An hour before the first prayer young men with beards, green headbands and banners gathered on rue Myrha to discourage worshippers from moving to the new site.
"No system in the universe can control us aside from Allah," shouted one young man. "There is more dignity in praying in the grass than in their false mosque," said another.
As the prayers began, dozens of young men belonging to a group called Forsane Alizza disrupted the service with shouts of "Allahu akbar" - "God is greatest" - and jostled with security.