About one in 10 German voters has an immigrant background, reports the BBC's Oana Lungescu. Their voice is becoming ever more important, with dozens of politicians of foreign descent running as candidates in Sunday's general election.
School-mates laughed when Oezdemir said he wanted to continue his studies
The new leader of the Green Party, Cem Oezdemir, is not your typical German politician. He was once voted the best-dressed man in German politics.
But there is something else that makes Mr Oezdemir distinctive. His parents came from Turkey in the 1960s, part of the wave of Gastarbeiter who helped rebuild Germany after World War II.
Thirty years ago, when young Cem Oezdemir told a teacher he wanted to continue his studies rather than become a factory-worker like his dad, his school-mates burst out laughing.
He has come a long way, but has Germany?
"I don't feel different because my parents came from Turkey to Germany," said Mr Oezdemir.
"I'm a party leader so part of my job is to fight for my party and get the best election results for my party.
"But the fact that people remind me that my name is Cem and not Hans or Gustav or whatever shows us that there's still a long way to go until we reach what my party stands for, that is a colour-blind society."
Nowhere to go
Some are now resorting to threats to prevent that vision from becoming a reality.
Oezcan Mutlu, who is also running for parliament for the Greens, showed me a letter he received at his home address at the weekend.
Apparently from the commissioner for the repatriation of foreigners, and couched in official language, it demands he go back to his country within three months.
But there is no such commissioner in Germany. The letter was actually sent by the far-right National Democratic Party (NPD) to about 30 candidates with foreign-sounding names, like Mr Mutlu.
"When I saw this paper, I was shocked," he said. "This is my home town. I am German. I have only German citizenship. I have no country to go to."
Mr Mutlu, a lawmaker in the Berlin state parliament, is used to hate mail.
"Until recently I got them from individuals anonymously, but this time a party with the name on it is addressing me privately," he said.
"You don't know what they can do if they have your address. I'm not afraid at all, but I have to be careful."
The letter says foreigners should be excluded from the welfare system and banned from owning land in Germany.
But of the 15 million immigrants here, only a third have the right to vote - including half a million people of Turkish descent.
The Berlin district of Kreuzberg has been dubbed Little Istanbul.
At the weekly Turkish market, most people speak Turkish, as well as German, and some of the stall-holders wear head-scarves.
When I asked a group of young men selling vegetable if they were planning to vote on Sunday, they shook their heads.
"I'd like to, but I'm not allowed," said one. "I'm a Turkish citizen."
Dual citizenship is restricted under German law, and many Turks who have made a home in this country are effectively disenfranchised.
"We have to stand and watch as others decide for us," complained one vegetable seller.
The Berlin district of Kreuzberg has been dubbed Little Istanbul
Those in the German Turkish community who are eligible to vote traditionally support the Social Democrats or the Greens.
But they are not the only foreign actors on the German political stage.
In a former warehouse, a couple are playing out a seduction scene, half-erotic, half-menacing.
It is a rehearsal at the small Russian theatre Russkaia Szena, founded by Ilia Gordon to cater to the large Russian community in Berlin.
Across Germany, 2.6m ethnic Germans from the former Soviet bloc are entitled to vote. Because of their experience under Communism, many back conservative parties. But Ilia will cast his vote for the Social Democrats.
He feels strongly that parties like the NPD, which he calls "fascistic", should be kept at bay.
"As somebody who comes from the Soviet Union and somebody who's Jewish, it's very important to me," he said. "And then I look which parties integrate immigrants to propel our interests."
Only two per cent of Germany's outgoing parliament - 11 MPs - come from a migrant background, while nine per cent of voters are of foreign descent.
It is the first time that the voter statistics have been made public.
"Nine per cent is a significant portion," said Andreas Wuest, project director at the Mannheim Centre for European Social Research and the only German academic who focuses on migrants as political actors.
"In one way or another, this share of the population can have an effect, especially in constituencies with higher levels of migrant voters, for instance in the bigger cities in the West."
So all the major political parties are fielding candidates from the fast-growing migrant communities.
There is a new leaflet out, in German and Turkish, explaining in simple language how the political system works here, and plans to publish one in Russian for the next election.
One of its promoters is Gabriele Guen Tank, the commissioner for immigrants in Berlin's Schoeneberg district.
Almost half of the youngsters in Schoeneberg, she said, come from a migrant background. Soon they will be eligible to vote.
"It's a big group coming," Ms Tank said. "And if we don't give them the chance of participation, we will have more problems in the future. So there has to be a change."
In his small office, Oezcan Mutlu proudly displays Barack Obama's election poster with the slogan: Change We Need.
But he does not expect to see a German Obama any time soon.
"I don't think that Germany is ready for an Obama - not as a chancellor, not as a president," he said. "Not even my grand-grand-children will see that, unfortunately."