Demonstrators from the large Turkish Muslim community in Germany have protested in Berlin outside a summit on integration
Four Turkish groups are boycotting the meeting, saying a new immigration bill treats Turkish-origin people and other immigrants as "second-class citizens".
The forum will examine ways to improve community relations, including teaching German in nursery schools.
About 15 million people with immigrant backgrounds are living in Germany.
The BBC's Tristana Moore in Berlin says the situation of Germany's 3.2 million Muslims, most of whom are of Turkish origin, has generated some anxiety, with fears that a lack of job prospects and the language divide risk creating an embittered Muslim underclass.
Ministers have long been concerned that ghettos are springing up in German cities, she reports.
Chancellor Merkel has invited members of the Muslim community and other immigrant groups to the conference.
But several Turkish community groups want the government to change the controversial immigration bill.
It stipulates that an immigrant who wants to bring a spouse to Germany has to prove the partner can earn a living and has some knowledge of German.
The new rules do not apply to German nationals who have foreign partners.
The government has ruled out making any changes to the new bill, which has already been approved by both houses of parliament.
The Turkish-German groups boycotting the forum have threatened to take the matter to the constitutional court.
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