Chau Chau was a playful young cat living in a 45th-floor Melbourne apartment until his owner's boyfriend threw him off the balcony.

The defenestration of the beloved pet has been declared a "tragic accident" after 20-year-old Cheng Lu admitted he used "a bit too much force" when trying to put the cat outside to teach it a lesson for scratching.

Cheng Lu outside court on Monday. Credit:AAP

Magistrate Costas Killias on Tuesday dismissed charges of animal cruelty and reckless endangerment against Mr Lu, finding the university computer sciences student threw the cat over the balcony but had no criminal case to answer.

"This was a terrible accident which led to the death of an innocent and apparently, on all accounts, playful pet. But it was not deliberate," he said.