About 70 protesters traveled from around France for this morning's demonstration in the city of Poitiers, which has symbolic meaning as the place where a French medieval ruler once drove away Arab invaders, regional prefect Yves Dassonville said by phone.
After police arrived, the protesters dispersed without resistance -- and three were detained to face accusations of "incitement of racial hatred" and damage to property, he said.
French TV broadcast images of dozens of rowdy, waving and chanting protesters on the mosque roof next to its minaret.
They unfurled a banner that read "Generation Identitaire" and demanded a referendum on immigration and mosques. The banner also bore the number 732, which Dassonville said was a reference to the year when the army of medieval French leader Charles Martel stopped an Arab invasion in Poitiers.
Muslim leaders said the protesters had disrupted a prayer inside, and expressed incomprehension over the stunt.
"We are thunderstruck ... These are people who are stuck in the year 732, and who don't see that the world has changed," Poitiers imam El Haj Boubaker told France's BFM-TV. "People can live differently than in a mindset of war and conflict."
France is home to Western Europe's largest population of Muslims, estimated to be at least 5 million even though the government does not provide official figures. Many have family roots in former French colonies in northern Africa.
French governments for years have struggled to integrate Muslims, who often pray in cellars, apartments and, at times, in the street because of a shortage of mosques in the country.
Dassonville said the completion of the Poitiers mosque has lagged for years because of ongoing troubles the Muslim community has had in drumming up needed financing. He said he was assembling an interfaith meeting of Jewish, Catholic and Muslim leaders in the city to show unity in the face of the far right demonstration.
Interior Minister Manuel Valls denounced a "hateful and inadmissible provocation" by the extremists.
Paris: Dozens of far right extremists stormed atop an unfinished mosque in western France Saturday to show their hostility toward it and denounce immigration that has brought millions of Muslims into the country, a regional official said.
First Published: Sunday, October 21, 2012, 08:43