Partner / Of Counsel
André KARG
Partner
Mr. André Karg advises his clients on the cross-border implementation of industrial projects, M&A projects, acquisition of companies out of insolvency and the creation of new market access.
During positions in major international law firms and in Franco-German legal relations, Attorney André Karg has gained extensive experience and in-depth knowledge in advising German, French and international companies in the areas of commercial law, international investments and M&A transactions. He is active both in an advisory capacity and before the courts, but prefers to plan projects with such foresight in terms of risk management and in the drafting of contracts that the partners, between whom there is usually still the cultural barrier of language, can resolve their conflicts themselves on the basis of their contracts.
Thus, cross-border consulting is one of the main activities of Mr. André Karg.
Commitment, creativity, pragmatism and humanity are the cornerstones of his consulting activities.
Dr. Stefan RINKE
Of Counsel
Dr. Stefan Rinke is a corporate lawyer and a acknowledged expert in contract law and litigation strategy.
His area of expertise includes advising tech companies, where product design through IT and competition law are just as much in focus as distribution law and industrial property rights. He also specializes in (individual) labor law in order to provide companies with holistic support in sensitive areas.
With his doctorate, he specialized in private international law and civil procedure law and handles cross-border legal issues with expertise in European procedural law. Dr. Stefan Rinke is an expert in litigation, which completes the drafting of contracts regardingthe effective enforcement of contractually stipulated rights and obligations.
Grit KARG
Partner
Mrs. Grit Karg advises German, French and international companies on all contractual and commercial law matters. She specialises in all issues related to product distribution.
This concerns in particular product conformity and product safety, the placing of products on the market and the selection of the distribution channel that is suitable for the product. Mrs Karg advises you on the structuring of your business relations and represents your company in disputes arising from your business relations. A particular focus of Mrs Karg’s work is in the area of data protection and compliance.
She has many years of experience in this area with process-oriented and agile project work.
She is also CIPM certified by the IAPP. This Designation indicates that Mrs Grit Karg has the necessary skills to establish, maintain and manage a privacy programme at all stages of its lifecycle.
Associates
Sascha GÖRS
Rechtsanwalt – Associate
Mr. Sascha Görs joined Ad Fontes as an associate in 2022 to support the team’s work in providing legal advice to our clients. Already during his university studies and subsequent legal traineeship, he specialised in IT and competition law as well as in issues of European law and private international law.
Further focal points of his work include labour law and general contract law. Mr Görs is passionate about legal issues concerning digital transformation and cross-border legal transactions. He contributes his expertise mainly in the area of contract drafting and for the purpose of effective legal enforcement on behalf of our clients.
Research assistants
Maya SIGL
Research assistant
Ms. Maya Sigl is a Legal Research Assistant in Ad Fontes’ team since December 2024. As a graduate of the German-French law program “BerMüPa” at the Humboldt University Berlin, she primarily supports the lawyers in researching and preparing cases in commercial and labour law.
Karolina WALSLEBEN
Research assistant
Ms. Karolina Walsleben is a Trainee Lawyer at Ad Fontes since 2025. During her law studies in Potsdam, Paris and Edinburgh and the acquisition of an LL.M. she was particularly interested in international law, criminal law as well as commercial, trade and corporate law. At Ad Fontes, she will gain practical insight into the exciting crossborder work of the law firm, particularly in the areas of labour law, tenancy law, general civil law and administrative law.
International Alliances
Marlies ULLENBOOM
Chargée des relations franco-allemandes
With the topic “International Alliances” Ms Marlies Ullenboom joined Ad Fontes to share her long experience with its founders. Marlies Ullenboom and André Karg met in Paris in 2013 and have been working together ever since.
A native of Berlin, Ms Ullenboom feels European since the early 1970s. Her professional life has always been international, whether as an employee or as a self-employed entrepreneur.
Around the turn of the century, Marlies Ullenboom realised that bilateral cooperation between German and French SMEs was almost non-existent. At that time, she joined an association of the German Mittelstand and took over the management of the association’s newly founded France representative office in 2007.
Ms Ullenboom’s concern was and remains the creation of French-German “tandems” so that they can jointly contribute to the development of Europe.
She is involved in regional networks of SMEs and in the French-German ecosystem. Information and exchange, meetings and travel for entrepreneurs and executives of small and medium-sized businesses are tasks to which Ms Ullenboom dedicates herself and thus accompanies Ad Fontes.
Cybersecurity
Sven ZEHL
Cybersecurity
Sven Zehl works with AdFontes law firm as a collaboration partner in cybersecurity. He brings many years of experience gained in management positions in the field of IT security. He is currently Head of Security at sevDesk GmbH. Previously, he headed data and cybersecurity teams at leading companies such as Bosch, Doctolib and Bitkom, where he developed security programs and obtained various certifications.
He has also participated in the development of national and international security standards and supported cybersecurity legislation at national and European level.
Drawing on his extensive expertise, he is particularly committed to the protection of businesses and start-ups, helping them to secure their digital infrastructures.
Certifications :
– ISO27001 Lead Auditor (CIS LA)
– Common Criteria Evaluator (BSI)
– Qualified auditor for CyberRiskCheck “CyberRisiko Check” from the German BSI (Federal office for information security)
Office management
Thibaut GÉRAUDIE
Office-Manager
Thibaut Géraudie joined Ad Fontes as Office Manager in January 2025 and has quickly established himself as the heart and soul of the firm. Trilingual like the firm’s lawyers, Thibaut is responsible for the efficient organization of the firm’s operations.
He oversees communications, resource management, financial administration and the use of office technology. In doing so, he supports the lawyers in achieving the firm’s primary objective: to provide trustworthy, prompt and high-quality advice.
Thibaut Géraudie is a state-certified foreign language correspondent in German, French and English. He has extensive practical experience in various fields, including as an accounts payable and receivable accountant at the Charité in Berlin, as an online marketing manager at an art gallery, as an administrative assistant at a digital consulting firm, and as a translator and assistant in the consular section of the French Embassy.