Protesters in Berlin gathered outside CDU headquarters.Thousands of demonstrators gathered in Germany on Thursday to protest the conservative Christian Democratic Union and Christian Social Union parties.

Tens of thousands of people took to the streets in cities across Germany on Thursday after a controversial motion demanding migration reforms was passed in parliament the previous day with support from the far-right Alternative for Germany (AfD).

The AfD party is polling at about 20% before Germany's February 23 elections, a record for a party. The mainstream conservative CDU/CSU alliance leads with about 30%.

Hundreds of people gathered outside the headquarters of Germany's opposition Christian Democrats (CDU) in Berlin on Wednesday evening to protest against the conservative bloc pushing through a motion to tighten migration policy with the help of votes from the far right.

A who's who of German talent signed an open letter calling for political leaders to "uphold democratic values" after a historic vote in the Bundestag that saw anti-immigration proposal pass with the support of the far-right.

German members of parliament held an emotional debate about whether to ban the far-right Alternative for Germany (AfD) on Thursday, after it helped to pass a controversial motion in parliament the previous day demanding hard-line migration reforms.

Protesters in Germany on Thursday rallied against the conservative CDU party to decry its cooperation with the far-right AfD in pushing through parliament a motion to demand a crackdown on immigration.