The 32-year-old has tied himself down at Loftus Road until 2016, subject to international clearance.
"The ambition of this club was presented to me by the chairman and the coach and I couldn't have been more impressed," the Brazilian told Rangers' official website.
"The desire to achieve things at this club is clear for everyone to see and I wanted to be part of that. I have come here to compete for the shirt and give my all."
Cesar spent seven years at Inter after joining from Chievo in 2005.