The "very ugly financial affair" relates to Dr. Kohl personally accepting some few Million D-Mark donations in cash for his party, the CDU. Thing is, donations to political parties must be declared in Germany, including names of the donators, to prevent corruption, and Kohl is refusing to state the names of the donators, because he "gave his word" to treat them anonymously.

This behaviour, as well as running these donations on segregated, undeclared accounts, is clearly a violation of law. One can only suspect there must have been some connection between the donations and political decisions during his term of office. The word bribery inevitably comes to mind.