What is left of the building is now a museum, and Mr Metzger caters for visitors seeking to crown their guilt-ridden pilgrimage with a culinary feast. "The Germans think this is a kosher restaurant," he chuckles. Kosher it is not. What little Jewish flavour he can provide has to be imported.
This in a city that before the war was one of the main centres of Jewish civilisation in the Western world. Weimar Germany had 520,000 Jews, about a third of whom lived in Berlin. There are 10,200 Jews left in the city, roughly a quarter of the country's total population.
Very few of them are what used to be called "German Jews", a species wiped off Germany's map by the Holocaust. You may find them at Crown Heights or in Tel Aviv, but not in Germany. The new denizens of the ghetto, living cheek by jowl with scruffy artists and techno-freaks, speak Slav languages and tend to be fourth-generation atheists.
"We are all survivors here," says Jerzy Kanal, director of the Jewish Community of Berlin. A Polish Jew in his 74th year, Mr Kanal lived through the Warsaw ghetto and the death camps and ended up in France, before wandering into Germany long after the war.
The older members of his community also hail from the occupied countries, but many settled in Germany not by choice, but because they had nowhere else to go. This rootless mass of wounded humanity was threatened with extinction until the German government came to its rescue. By extending a welcoming arm to anyone in the former USSR who was able to prove Jewish ancestry, Bonn tipped the demographic balance.
The influx of new blood has been a mixed blessing. Less then half of the 40,000 immigrants have been recognised as Jews by the Hallacha law, which requires proof that the applicant's mother was Jewish. Those who are accepted must traverse a multitude of cultural boundaries in one leap.
The new arrivals are nurtured in a ramshackle building next to the New Synagogue. The community centre, funded by the German authorities, arranges accommodation for the immigrants, inducts them in the Western and Jewish ways of life, and helps them find jobs. Unemployment among Jews from the former USSR runs at over 90 per cent.
But the sheer force of their numbers is making a difference. Jewish life is taking root again in the cursed soil, spawning a new generation whose first language will again be German.
The entrance to the most potent symbol of Jewish resurgence is guarded by El-Al type security. Behind the shock-proof windows of the Heinz Galinski school in a suburb of Berlin, 240 pupils are learning Hebrew, eating kosher meals and mumbling the long-forgotten prayers of their ancestors.
"We are a school with a mission," says Norma Drimmer, of the executive board of Berlin's Jewish Community. "You need a place where you can find your roots and feel normal."
The school, opened last September, was the first such institution to have been built in Germany since the war. But the building maintains a tenuous link with the past by incorporating a piece of wall rescued from the New Synagogue.
The biggest problem is keeping the Germans out. There is a long waiting list, and a quota for German children, whose parents are prepared to pay up to DM400 (pounds 172) in monthly fees.
It is a fitting tribute to the way way relations have changed. Anti- Semitism lingers, but on the list of "foreigners" Germans dislike most, Jews are at the bottom. "Federal Germany is not Hitler's Germany," Mr Kanal says. "The German people have in large part atoned for the crimes of the past."
The Jews of Berlin often find themselves leaping to the defence of their country. They have been in action again recently, condemning an American book which blames all Germans for the Holocaust.
Hitler's Willing Executioners, by Daniel Goldhagen, a Harvard assistant professor, has provoked a furious debate in the German press, but most of the vitriol has emanated from Jewish pens. "The major point Goldhagen makes is that German anti-Semitism was so vicious, and Germans had such bloodlust, that killing Jews was something they did with great relish," says Edward Serotta, an American Jewish writer living in Berlin. "I myself side squarely with the great majority of American and Israeli Holocaust scholars, who have dismissed the book as self-promoting and sensationalist."
The community also gives short shrift to members of their faith abroad who would prefer to limit the Jewish presence in Berlin to tombstones. When Ezer Weizman, the Israeli President, came here expressing incomprehension about Jews wanting to live in Germany, he was angrily sent packing.
"Many people in Israel ask why Jews are living here," says Mr Kanal. "There is no general answer . . . Everyone must give their own reason."
For Mr Metzger the reason is very simple: "Hitler wanted to eradicate all the Jews from Germany. If we weren't here, Hitler's dream of a Final Solution would have been fulfilled." Would he nevertheless prefer to live in America? "No way," he says. "America has enough Jews already."
Population: 10,200. Pre-war population: 170,000.
Number of Jews aged over 60: 3,000.
Synagogues: Six, including one Orthodox.
Schools: Two, plus one kindergarten.Reuse content