"Berlin wears a yarmulke," the popular BZ local newspaper declared to its readers on Saturday. The reason: the front page presented a photo of five Berlin celebrities posing with skullcaps – including Mayor Klaus Wowereit, one of the best known gay politicians in Europe.

The city's residents decided to show their solidarity with the city's Jewish community following Tuesday's attack on Rabbi Daniel Alter. The assailants, locals of Arab origin, asked Alter - who was wearing a yarmulke - if he was Jewish, and then proceeded to attack him. On Thursday a rabbi was attacked in Vienna by soccer fans who abused him with anti-Semitic and Nazi slogans. A spontaneous rally was held in the city on Saturday.

Reinhard Naumann, head of the Charlottenburg– Wilmersdorf Berlin district, called for immediate action in response to the events. Naumann called on the Berlin newspaper to take action: "Berliners can show solidarity with Daniel Alter and the Jewish community by wearing skullcaps," Naumann told BZ on Friday.

The newspaper decided to accept the challenge, and turned to politicians, celebrities and citizens, who all agreed to pose wearing skullcaps. Sven Schulz, a parliament member from the Spandau neighborhood, explained: "'Berlin wears a yarmulke' is an excellent idea, and is a powerful symbol of solidarity."

Mayor Wowereit published a notice of support for the rally, calling the attack on Alter "violence directed against peace and communality in a multi-religious city… Berlin is proud of its liberal and tolerant heritage. Our multi-national city includes numerous religious communities. Churches, synagogues, mosques and temples are all communal centers and carry an important social role."

A Facebook initiative also led to a demonstration which saw 150 people, most of them wearing skullcaps, marching through the streets. "We cannot accept the fact that people can be attacked in our streets only because they [are] identified as Jews," the organizers explained.

The demonstration was also meant to send a message to a Rabbinical College near Berlin, which advised its rabbis not to wear skullcaps on the street.