"We have come to a decision to file a criminal complaint against Chancellor Friedrich Merz," AfD MP Stephan Brandner said in a video posted to X, calling Mr. Merz's remarks in parliament "reprehensible".
"The word 'remigration' is nothing other than a synonym for ethnic cleansing," Mr. Merz said of the AfD's flagship slogan.
"Remigration is nothing other than ethnic cleansing by skin colour and origin. "
But some on the far right have also used the term to mean the deportation of migrants and even German citizens of foreign origin.
Brander, the AfD lawmaker, called Mr. Merz's comments "nonsense" and said it was "unacceptable for the head of the executive of our country to come up with such lies and slander".
Germany, like many countries, offers parliamentarians immunity for comments made in the chamber.
Outside of parliament, Germany's laws around free speech have been the source of considerable controversy in recent years, with critics -- including some within the AfD -- contending that strict rules stifle expression.
There have been several high-profile cases in recent years of people being criminally investigated for insulting, mocking or harshly criticising political figures.
One man, for instance, was fined by a court earlier this year for referring to Merz in an online comment as a "Lackaffe" -- roughly meaning a snobbish dandy -- while others have been investigated for calling him "Pinocchio" and "Lying Fritz".
