Both articles describe the transfers as misappropriations of funds. These transfers were a revelation not only to Nissan, but also to Renault. They prompted probes in both France and Japan (and likely will, at this point, in the United States), it fits a pattern of embezzlement.
Broadly speaking, if management finds their operational budget in their personal account without the Board's knowledge, that's fraud.
The Japanese criminal-justice system is deeply flawed. But allegations are made in multiple cases across multiple jurisdictions and describe seriously criminal behavior.