Bonucci joined Union Berlin for free in August after being frozen out of the Juve squad following a reported fallout with manager Massimiliano Allegri.
“I have decided, after great suffering, to pursue a lawsuit against Juventus,” said Bonucci, 36.
“I felt drained of everything, humiliated.”
He was left out of Allegri's squad for the United States pre-season tour and home friendlies prior to the start of the 2023-24 Serie A season.
“My rights stipulated that I should have trained with the team regardless of the technical choice and been put in a position to physically be able to play during the following season,” Bonucci added in an interview with Sport Mediaset published on Thursday.
“This was not granted to me, I no longer trained with the team. I couldn't do what I love most.
“I am pursuing this cause because the people who were supposed to let me end my career with Juventus in a respectful and worthy way have not done so.”