Wolfgang Kubicki, an FDP lawmaker, has said he is unconcerned about the lawsuit.
Turkey’s President Recep Tayyip Erdoğan is suing a senior German MP who called him a "little sewer rat".
Erdoğan's lawyer confirmed on Friday that the Turkish leader had filed a criminal complaint for insult and defamation.
A Turkish law banning insults against President Recep Tayyip Erdoğan has been condemned by the European Court of Human Rights (ECHR).
Wolfgang Kubicki, a German lawmaker with the coalition Free Democratic Party (FDP) has said he is unconcerned about the lawsuit.
Kubicki had used the term “sewer rat” in reference to Erdoğan while talking about a migration deal between Turkey and the European Union.
The comments about Turkey's refugee policy were sharply criticised by Ankara, and Germany's ambassador to the country was summoned over the matter.
Kubicki later said he considered sewer rats to be “small, cute, but also clever and devious creatures” that sometimes appear as protagonists in children’s stories, such as "Ratatouille".
A spokesperson for the public prosecutor's office in Hildesheim, near Cologne, confirmed that they had received the complaint from Erdoğan's lawyers.