al-AP is reporting that 100 professors in Germany are being investigated for allegedly accepting bribes from a company acting as an intermediary between PhD students and the professors. The students paid the company for help in getting doctorates through the company's extensive contacts with the professors--although I can't imagine what kind of "help" the students expected for the thousands of dollars they each paid--but there's no evidence yet that the students knew of outright bribes.
One professor, convicted of taking such bribes last year, received a 3 year prison term.
I would provide a link to this story, but given their attacks on people who quote "their" stories even in fair use, I no longer link to al-AP. Should you want to find the actual story, you might find it by doing a search for the company in question, Institute for Scientific Consulting.