Rosinus Partner > Frankfurt, Germany > Firm Profile

Rosinus Partner
Windmühlstraße 1

White-collar crime > Advice to companies Tier 4

Led by Christian Rosinus and Mathias Grzesiek, Rosinus Partner offers large companies and start-ups criminal law advice at the interface with compliance, including risk analyses in the areas of money laundering and corruption, while also frequently acting at the interface with criminal and corporate law. The appointment of Janina Brandau to salary partner in January 2023 strengthened the capacities in criminal tax and sanctions law. This is complemented by forensic experience in supporting internal investigations.

Practice head(s):

Christian Rosinus; Mathias Grzesiek

Other key lawyers:

Work highlights

  • Advising a start-up from the technology sector on criminal law issues in connection with an M&A deal. The subject of this was the sale of shares to a private equity investor. Given that investigations were being carried out against minority shareholders, a solution had to be found in close coordination with the law enforcement authorities that took into account money laundering risks and existing criminal arrests of company shares.
  • Advising a financial services provider on the seizure of customer assets in their accounts. Advice as a secondary party in criminal proceedings.
  • Advising a private equity investor in connection with misconduct by a managing director of a portfolio company. Carrying out factual analyzes and supporting an investigation in connection with diesel emissions.

White-collar crime > Advice to individuals Tier 4

Rosinus Partner 's commercial and criminal tax law expertise is called upon by a diverse range of private and public individuals in the context of individual defence, including managing directors, PE managers or influencers, which face allegations of commercial and criminal tax law allegations, whereas traditional diesel emissions, cum-ex and cum-cum proceedings continue to contribute to the team's workload. The renowned commercial criminal lawyer Christian Rosinus jointly heads the practice with Mathias Grzesiek, who focuses on criminal IT and cyber crime as well as data protection, while Janina Brandau, who made partner in January 2023, frequently assists with criminal tax law matters.

Practice head(s):

Christian Rosinus; Mathias Grzesiek

Other key lawyers:


Quick perception.

‘Strong communication skills, dynamic, top professional skills.’

‘Mathias Grzesiek: Technically outstanding, special expertise in IT and cyber criminal law.’

‘Christian Rosinus: Experienced, strong communicator, analyst.’

‘It is impressive how Christian Rosinus and his team have established themselves in the criminal defense market and all well-known criminal proceedings in just a few years. The law firm is characterized by the fact that all leading partners are experienced business lawyers who not only know criminal law, but also excel in all related legal areas, such as corporate law, tax law and business law. They have a thorough understanding of complex issues relevant to criminal law.’

‘Christian Rosinus is one of the leading charismatic criminal defense lawyers in Germany, who, with his razor-sharp intellect and fluency, is able to understand and analyze complex issues in a very short time.’

‘Young, dynamic and extremely qualified team. Client service is very important here.’

‘Christian Rosinus: Extraordinarily smart and experienced; a good and trustworthy partner at our side.’

Work highlights

  • Defending the managing director of an international crypto exchange against allegations of money laundering.
  • Advising a managing director of a financial services provider on criminal allegations in connection with the provision of accounts.
  • Defence of a suspect in cum-ex and cum-cum investigations.

Compliance > Internal investigations Tier 5

Rosinus Partner focuses on compliance and investigations, including matters pertaining to allegations of corruption, cum-ex, embezzlement as well as the diesel emissions scandal. Criminal lawyer Christian Rosinus and Mathias Grzesiek, who specialises in cyber-based criminal law, IT criminal law and data protection, jontly head the practice. Janina Brandau (white collar crime and tax law) was appointed to partner in January 2023.

Practice head(s):

Christian Rosinus; Mathias Grzesiek

Other key lawyers:


Rosinus Partner is up to date with all technical support, e.g. secure data room for uploading documents, online questionnaires designed for clients that can be technically evaluated and its own server .’

Christian Rosinus, as the name partner, is absolutely quick in reacting, in organizing the necessary measures and in putting together the team.

The team quickly grasps the current issues and then provides thoughtful and tactically sound advice on how to proceed with the matter. The team also knows how to read a room – they know when to push and when to back off.

Christian Rosinus: An excellent team leader and a very smart lawyer. He has good personal contact with customers and is very responsive.

Key clients


Work highlights

  • Internal investigation for a leading international chemical company into questions of potentially criminally relevant employee misconduct.
  • Conducting an internal investigation at a portfolio company of a private equity advisor in connection with the breach of trust of a former managing director and the successful enforcement of claims for damages amounting to millions.

In the City of Frankfurt am Main, located near the Holbeinsteg, we are a nationally and internationally active firm specialising in providing clients with advice and defence in relation to white-collar crime and tax offences, compliance, regulatory penalty and sanction procedure and management liability. Our expertise extends to all significant sectors in this field of activity.

Before founding Rosinus I Partner we worked for many years in leading national and international corporate law firms. We therefore have a wide understanding of commercial interaction and the support and control of official proceedings and compliance projects.

Our private and commercial clients have faith in us because, thanks to our expertise and experience, we are able to provide successful support in avoiding and/or minimising personal and commercial losses in connection with official proceedings and achieving discreet solutions with our strategic vision. We act conscientiously, with implementation and bargaining strength, and on occasion apply our creativity to achieve unusual solutions.

We work in teams, often cross-border and international. We have a wide-ranging network of both national and international partners available to us with whom we can supervise and conduct even large-volume proceedings and projects from a single source.

Our clients can be sure that we act professionally at the highest level and have our fingers on the pulse. This is reflected in our market perception in the media and academic publications.

All this makes us sought after sparring partners for (inter)national corporate law firms as well as accountants and tax consultants, with whom we collaborate in our working languages of German and English.

We value people who, like ourselves, have a diversity of interests and can look beyond their own horizons. Our work forms a significant part of our lives and we pursue it in a spirit of enjoyment and great passion. If necessary, therefore, we make ourselves available to our clients and can be contacted around the clock on any day of the week.

However, we also draw our creativity strength from taking time to be there for our families and pursuing other interests. This attitude is appreciated by clients as well as by our present and future colleagues to whom we give the opportunity of a career in our dynamic environment.

Contacts : Dr. Christian Rosinus, Dr. Mathias Grzesiek
Number of lawyers : 6
Languages : German, English, Portuguese, French, Spanish