There is no evidence that Dutch social psychologist Diederik Stapel had faked any data for his Ph.D. work, just evidence he had faked a whole lot since.  Still, a panel recommended The University of Amsterdam look into his work and perhaps revoke his doctorate "on the grounds of exceptional academically unworthy conduct."

Ph.D.s in Europe are a little different than in the U.S.A. because Jan Hendrik Schön had the same thing happen when he was discovered to be a fraud.  In America, you pay to go to a university so you own the degree. In Europe, it seems to be more of a license so if they don't like you, they just take it back.  No refund on your time spent.  Actual proof of fraud is a no-brainer, of course, but these often seem to be punitive rather than evidence-based.

It was believed most of Stapel's old data had been destroyed, so nothing could be proven about his thesis, but he isn't taking any chances - he revoked his own Ph.D, according to this statement released by the university.

UPDATE: Disgraced Dutch Pyschologist Returns Doctoral Degree by Martin Enserink at Science