Well there are some sanctions in place, but even if you're not violating sanctions there are various laws that could have been broken related to money laundering and tax evasion, registration of foreign agents, and the Foreign Corrupt Practices Act. I'd be most worried about violations of the Bank Secrecy Act.
Sanctions in place?? Really...Germany has many active deals with Russia and Ms. Merkel is really p***** with the new sanctions because they effect EU dealings.