A blaze engulfed the rented villa Breno shared with his family in the upmarket Munich suburb of Grünewald on September 20 last year, resulting in millions of euros worth of damages.
During the trial, which has been running since mid-June, the prosecution argued that the 22-year-old Brazilian defender had intentionally started the blaze, acting out of frustration with a protracted knee injury, Die Welt daily reported on Wednesday.
Nobody was hurt in the fire, but prosecutor Nicolas Lanz said this was only because Breno's wife and children had left shortly before it began.
Before the incident Breno - full name Vinicius Rodrigues Borges - had been getting psychiatric help at the renowned Max-Planck Psychiatry Institute, a fact many blamed on his chronic knee pain.
Reports suggested he had also developed a drinking problem during his extended recuperation.
Yet despite his documented psychiatric problems, the Munich Regional Court did not see sufficient cause for mitigating circumstances when considering the length of Breno's sentence.
Meanwhile, the footballer's defence lawyer Werner Leiter pleaded for acquittal on the grounds of lack of conclusive evidence, and high alcohol levels in Breno's bloodstream at the time the fire began.
“There remain doubts over what really started the fire on that chaotic night,” Breno's defence lawyer Werner Leiter told the court.
Breno will now have to give up hope of moving to the Italian club Lazio, which had already drawn up a contract with the defender following his departure from Bayern on June 30.
The deal hinged on the condition that Breno received no prison sentence in Germany.