The 62-year-old had admitted to tax evasion in January last year. For years, he had made large profits in stock market speculations via a secret Swiss bank account.
By choosing to go public, Hoeness had opted for what German law calls "voluntary disclosure": evaders can avoid trial by correctly detailing the taxes they have skipped and paying them back with 6% interest.
But during this week's trial, it not only emerged that the sums Hoeness had evaded were almost ten times higher than assumed – previous reports had spoken of €3.2m (£2.6m) – but also that he had failed to disclose his accounts within the rules.
An effective voluntary disclosure would have had to be done with the same detail as a tax return, the chief prosecutor had said. Hoeness had provided end-of-year statements for the relevant period, but failed to provide sufficient details on individual taxable transactions.