Rosinus Partner possesses extensive expertise in internal investigations, regularly serving as an independent ombudsperson for clients. Led by Christian Rosinus, Mathias Grzesiek, and, since 2025, Mirjam Steinfeld, the team conducts meticulous investigations into workplace issues, including potential compliance breaches and misconduct, while carefully assessing reports from employees and whistleblowers. In 2025, Arthur Leonhardt joined the practice from Clifford Chance, while Janina Brandau departed to take up a position with the tax authorities.
Legal 500 Editorial commentary
Accolades
Client satisfaction: Lawyer & team quality
Testimonials
Collated independently by Legal 500 research team.
- ‘Their team is extremely responsive while being very sensitive to the client's and the case's needs and particularities. It's always great to work with them and to benefit from their vast and international network.’
- ‘Mirjam Steinfeld has impressed us with her broad knowledge, responsiveness, commitment, and remarkable confidence and strong presence.’
- ‘Since I worked with Christian Rosinus, I can say that the team members were very friendly when joining our meetings.'
- ‘Christian Rosinus is very smart and analyses the case and the necessary steps very quickly.'
- ‘Christian Rosinus and his team are an excellent, responsive group of people. They have a can-do attitude and provide clear, pragmatic advice, which sets them apart.’
- ‘Christian Rosinus knows how to handle an investigation. He is discrete and authoritative and looks for pragmatic solutions to challenging problems.’
- ‘The law firm was retained and consulted in connection with compliance investigations. The colleagues are client-oriented, multilingual, and meet the necessary IT standards, such as providing separate data rooms.'
- ‘Christian Rosinus and Miriam Steinfeld are skilled at explaining criminal law issues to clients in a clear and understandable manner. They strive to find viable and practical solutions for their clients in sensitive situations.'
Key clients
- Battenfeld Cincinnati
- GEW Wilhelmshaven
- Magura Bosch
- VDE e.V.
Work highlights
Advised a capital investment company, an investment company in the pharmaceutical industry and an insurance company regarding internal investigations.
Lawyers
Next Generation Partners
Junior partners with significant recognition from clients and peers in the market and key roles on multiple matters.
Practice head
Christian Rosinus; Mathias Grzesiek; Mirjam Steinfeld
Other key lawyers
Arthur Leonhardt