According to his lawyer, ex-tennis star Boris Becker (55) reported influencer Cathy Hummels (34).
"I filed a complaint for my client," said attorney Samy Hammad of the German Press Agency.
He accuses Hummels of public defamation.
"Anyone who defames my client in public in the future must expect a harsh reaction from my client and from me," Hammad said.
"It is enough."
Ad receipt not yet confirmed
The “Bild” newspaper had previously reported on the ad.
The background is said to be statements by Hummels in a podcast about Becker and his prison sentence for delaying bankruptcy.
According to Hammad, the complaint was filed with the Munich I public prosecutor's office.
There you could not confirm the receipt on Monday.
"Since my client does not know the content of the criminal complaint and the specific allegation, she cannot comment on the matter," said Hummels' lawyer Stefan Ventroni of the dpa.
"Regardless of this, Ms. Hummels stands by the view expressed in her podcast "sHitstorms" that when a court sentence is imposed - regardless of the crime - other standards should not be applied because of a "celebrity bonus".
Hummels said to the "Bild" newspaper: "I wish Boris Becker a nice year 2023." She pointed out that she met Becker's wife Lilly on vacation in Dubai.
"She also sends her greetings." Hummels posted a video of this encounter on Instagram a few days ago.