A spokesman for the court in the western town of Kassel said the 48 year-old Austrian mechanic was accused of violating laws on illegal organ trading for offering his kidney as a "blood purification organ" online at a starting price of 66,500 euros (46,700 pounds).
He was hoping to use the proceeds to ease his girlfriend's financial worries, said court spokesman Theodor Weber.
"Apparently the firm she worked for was in trouble and he wanted to help them out," he said