A Tense Cultural Rift Racks Germany's Former "City of Diplomats" Henning Kaiser/DPA, via Agence France-Presse - Getty Images Police searched a man who attended a demonstration called by a Muslim Salafist movement against the small extreme-right party, the Pro-NRW, in Bonn on May 5. BONN - The people who live in the trim row houses with well-tended gardens that line the streets of this spa town along the Rhine like to boast of their city's tolerance as the onetime home to dozens of foreign embassies, when Bonn served as capital of West Germany. "We used to be a city of diplomats," said Christa Menden, who owns a flower shop. But since the capital of the reunited Germany decamped to Berlin in 1999, the diplomats have gone. In their place is an expanding population of Muslim immigrant families, many of whom moved into the neighborhood of Bad Godesberg to fill the housing glut left behind. Today once-tranquil Bonn has become known as a volatile cocktail of social tensions, between its Muslim newcomers, who include some German converts as well as immigrants from Arab-speaking countries, with some hard-core elements, and a far-right nationalist group that has mounted a growing campaign against them. Last month, some 200 Muslims, many from other cities, gathered to defend the honor of their prophet after the far-right party, the Pro-NRW (for North Rhine-Westphalia), threatened to display caricatures of Muhammad as part of an anti-Muslim rally in front of the King Fahd Academy, an Islamic school built with Saudi money in 1995. The authorities had tried but failed to win a court injunction preventing the rightists from doing so and instead tried to park police vans to block the view. But after one of the 30 or so rightists climbed on the shoulders of another to flash the offending cartoon at the Muslims, who had just finished praying, a shower of rocks and shards from smashed flower pots flew at the police. "They just exploded," said Robin Fassbender, a prosecutor in Bonn, who has started an attempted-murder investigation against a 25-year-old Muslim protester who sneaked through the police barrier and stabbed three officers, wounding two seriously. By the time the rioting stopped on May 6, the police had rounded up 109 Muslim protesters, many of whom had traveled to Bonn from elsewhere in Germany, according to the police. "They viewed the police as an organ of the state that wanted to insult Muslims by failing to prevent the caricatures from being shown," Mr. Fassbender said. That is a different dimension of violence than these officers are used to. They are trained to regularly take stones and broken bottles, but not be specifically attacked like this. Days earlier the same far-right group had held a similar protest in Solingen, where the Muhammad cartoons were also paraded. The police in Solingen detained 32 Muslim protesters after they clashed with officers, throwing stones and charging barriers separating them from the far-right demonstrators. The violence, which was preceded by a nationwide Salafist action to hand out Korans in inner cities, has refocused the authorities" attention on what they see as the threat posed by the Salafist movement. The German interior minister, Hans-Peter Friedrich, has now vowed to take stronger action against the Salafists. While they account for a tiny fraction of the estimated 4.3 million Muslims living in Germany, he noted, nearly all Islamic extremists known to German security officials have links to the movement, which includes several charismatic preachers. They have proved savvy at using social media and Internet forums to attract young followers in Bonn and surrounding areas. The King Fahd Academy, where the clashes with the police took place, stands incongruously in the tidy neighborhood of Bad Godesberg, its gold-topped minaret rising against the deep green bluffs of the Drachenfels crag, where legend has it that Siegfried slew the dragon. Built by the Saudi government, the school was intended to offer a traditional Arabic curriculum to children of diplomats stationed in Bonn. The city authorities tried to close the school in 2003, after it emerged that it taught an extreme form of Islam that encouraged a violent rejection of the Western humanistic values enshrined in the German Constitution.