Netflix Fraudster Carl Rinsch Headed to Prison Despite Keanu Reeves' Plea

Keanu Reeves went to bat for his old director ... but it wasn't enough to keep Carl Rinsch out of prison after the filmmaker was sentenced in his $11 million Netflix fraud case.

Here's the deal ... Keanu personally wrote to the judge asking for leniency for Carl -- who directed Keanu in the 2013 movie "47 Ronin" -- calling Carl an "exceptional artist" while acknowledging Carl has a tendency to self-sabotage. Keanu also praised Carl's unfinished Netflix series at the center of the case as "superb and visionary."

The heartfelt endorsement didn't carry the day, though ... a federal judge sentenced Carl to 30 months behind bars Monday after he was convicted of wire fraud, money laundering and other financial crimes tied to the failed project.

Prosecutors said Carl convinced Netflix to wire him $11 million to finish "White Horse" ... but instead funneled the money into personal accounts before blowing it on luxury cars, designer goods, high-end furniture and risky investments instead of the production.

Prosecutors had sought five years in prison, while Carl's attorneys pushed for probation. In addition to the prison sentence, he was sentenced to three years of supervised release and ordered to forfeit $11 million.