Practice Areas
Dr Constantin Rehaag is a partner in Dentons’ Frankfurt office and Europe Co-Head of the Intellectual Property, Data and Technology Group, as well as Head of the IP/T practice in Germany. He brings 15+ years’ experience in IP and unfair competition litigation, anti-counterfeiting and related criminal law, and trade secrets, complemented by trademark and design prosecution for leading domestic and global companies across sectors including pharma, e-commerce, luxury and fashion, automotive, entertainment, and technology. His contentious practice spans trademark, design, copyright and patent disputes, including patent infringement proceedings conducted with patent law firms before specialist chambers, and he regularly advises on privacy issues in crisis contexts, especially where unfair competition concerns arise.
Recognised for steering complex, multi-aspect IP litigation that blends trademarks, designs, copyright, patents, competition and criminal enforcement, Dr Rehaag has led headline matters including representing the world’s largest e-commerce company up to the German Federal Court of Justice, advising a market-leading German pharmaceutical company in the largest known case of illegal sales of pharmaceuticals in Germany, coordinating cross-border patent disputes for industry leaders, and securing and enforcing trade secrets and algorithmic IP for leading technology clients. He is also a legal expert to the EUIPO Observatory and a member of its Legal Expert Group, which supports the European Commission on case law and studies across trade secrets, copyright, blocking orders and other IP topics, and he teaches as a lecturer in law at the University of Passau, provides advanced training for judges and prosecutors at the German Judicial Academy, and delivers courses at EUROJUST-thought-leadership that underpins his courtroom strategy.
Areas of Expertise:
• IP and unfair competition litigation. Acts in complex multi-right disputes (trademarks, designs, copyright, patents), including coordination with patent firms in infringement proceedings before specialist courts.
• Trade secrets and evidence. Designs and implements trade secret protection and compliance programmes, and litigates high-stakes business secret theft matters; his publishing record includes analysis of burden of proof issues in IP, underscoring authority on evidentiary law in IP disputes.
• Technology, platforms, and competition interfaces. Experience includes antitrust litigation for the world’s largest e-commerce company up to the Federal Court of Justice, and protection of algorithms and sensitive technical know-how for leading technology clients-touchpoints that are increasingly salient for AI and IP mandates.
• Criminal IP and anti-counterfeiting. Combines civil and criminal enforcement strategies; co-authored a leading handbook on IP-crime and other works on criminal trademark infringement, evidencing strong practitioner-scholar credentials in this field.
• Brand strategy and prosecution. Advises on portfolio strategy for leading brands in luxury, fashion, mobility, and consumer products, including registrations, customs measures, and coordinated cross-border enforcement.
Career
Partner, Dentons (Frankfurt), 2015-present; prior roles include Counsel at Dentons/Salans and Associate at Mayer Brown.
Lecturer in law (University of Passau); faculty at the German Judicial Academy for advanced judicial/prosecutorial training; EUROJUST trainer for EU Member State prosecutors.
Certified specialist lawyer for intellectual property law (Fachanwalt für gewerblichen Rechtsschutz) and frequent conference speaker on litigation and trade secrets.
Work Highlights
• E-commerce and competition success: Successfully represented the world’s largest e-commerce company in trademark and antitrust litigation up to the German Federal Court of Justice, demonstrating capacity to carry complex platform-related disputes through to the highest level.
• Major pharmaceutical enforcement: Advised a market-leading German and Swiss pharmaceutical companies in civil and criminal proceedings in the largest known case of illegal sales of pharmaceuticals in Germany, showcasing blended civil/criminal strategy and sector acuity.
• Patent disputes across industries: Represented a global market leader in tissue, a Swiss pharmaceutical company (Germany and Hungary), and a Polish glass manufacturer in patent infringement and invalidity proceedings, underscoring courtroom experience in technically complex cases.
Experience
• Trade secrets and crisis mandates: Implemented business secret programs for pharma and chemical clients; pursued civil and criminal proceedings to recover stolen business secrets (including against a former director of a German affiliate), and defended a pay-TV channel against brute force attempts targeting confidential information.
• IP protection for technology and AI-adjacent assets: Represented an American multinational technology company on IP litigation and protection of algorithms, aligning with emerging AI/IP protection strategies and confidentiality controls for high-value code and models.
• Brand and design enforcement: Enforced rights for toy and luxury/fashion clients; advised on design registration and subsequent enforcement for MFP manufacturers, reflecting a cradle-to-court approach to product IP.
• Cross-media and content matters: Defended a world-leading printing press manufacturer in a copyright claim and advised a music industry client on securitisation of a major portfolio in Germany, bridging IP with financing and media.
