CMS is renowned for its well-established and sizeable data protection team, composed of highly experienced and specialised lawyers with strong technical expertise and extensive international reach as well as its ‘deep expertise and pragmatic approach’. The team, led by Dóra Petrányi, a leading data protection lawyer in Hungary, offers a full range of data protection and privacy services. Katalin Horváth, newly promoted to partner, brings expertise in technology, fintech, AI and cybersecurity matters. Márton Domokos coordinates the firm’s CEE data protection practice, focusing on IT, e-commerce, cybersecurity and AI law. Péter Homoki specialises exclusively in IT, data protection and telecommunications law, further strengthening the firm’s capabilities in tackling complex, technology-driven legal challenges.

Legal 500 Editorial commentary

Testimonials

Collated independently by Legal 500 research team.

  • ‘What truly sets them apart is their deep expertise and pragmatic approach. They are not only well-versed in the complexities of data protection regulations but also excel at providing practical, business-oriented solutions tailored to our specific needs. Their ability to navigate both local and international data privacy laws has been invaluable to our global operations. I would highly recommend them to any business looking for a reliable and forward-thinking partner in data privacy.'

  • ‘Katalin Horváth stands out for her deep understanding of data privacy regulations and her ability to translate complex legal frameworks into practical, actionable advice. What I value most about Katalin is her proactive approach—she anticipates potential challenges and addresses them before they become issues. Her attention to detail, combined with her strong communication skills, makes it easy to trust her guidance. Katalin's dedication to her clients is unmatched, and her expertise sets her apart from others in the field.'

  • 'Márton Domokos has been invaluable in managing our data protection needs. His knowledge of data privacy law is vast, but what really differentiates him is his ability to provide tailored solutions that align perfectly with our business objectives. I particularly appreciate his clear, concise explanations of legal concepts, which make complex data protection issues much easier to navigate. Márton’s collaborative and solution-oriented mindset makes him a standout in the field, and his commitment to client service truly distinguishes him from competitors.’
  • ‘They have a deep understanding of the business processes and a strong client-supporting attitude. CMS team can easily understand the client's situation and communicate very clearly in connection with the possible legal solutions.’

  • ‘The team is always available and can be contacted immediately in emergencies. They are prepared to give a quick and clear response, taking into account the business interests.’

  • 'Dóra Petrányi stands out for her ability to distil complex issues into straightforward, practical guidance. Her close relationships with national regulators enhance her ability to navigate complex investigations and ensure smooth regulatory interactions.'

  • ‘Márton Domokos is literally the best privacy lawyer in the Hungarian market. Everything that is connected to privacy and data protection by any means, he knows for sure. He is aware of any recent regulatory change even to the slightest amendment. He proactively follows up on what our company needs to update in order to fully comply with the privacy-related regulations.'

  • ‘CMS Hungary's data privacy and data protection team stands out for its exceptional expertise and extensive experience working with international clients. The team’s strong relationships with national regulators, combined with their deep understanding of both Hungarian and EU regulatory frameworks, ensure they deliver effective, practical advice tailored to complex cross-border matters.’

Key clients

  • Microsoft Hungary
  • Baumit
  • BP
  • Raiffeisen
  • Kyndryl Holdings, Inc
  • Samsung Electronics
  • RTL Group (Bertelsmann Group subsidiary)
  • Magyar Telekom Plc., IT Services Hungary (Deutsche Telekom subsidiaries)
  • OTP Mobile Ltd. and HelloPay PLC
  • Vinted

Work highlights

  • Advising Samsung Electronics on day-to-day data protection matters regulatory issues, contracting procedures and the local feasibility of global features.
  • Advising Microsoft on a wide array of data protection matters and their strategic projects for over a decade.
  • Advised Partner in Pet Food on the introduction of an AI-powered image processing workplace safety and security software application, including the review of the underlying agreement with the service provider and the analysis of the regulatory (data protection, cyber security and AI) aspects.

Lawyers

Leading associates
Leading associates with regular involvement in their team's key work, and recognition from peers or clients as being ones to watch.
Márton Domokos
CMS
Leading partners
The strongest partners in their field, leading on market-leading deals and endorsed by peers and clients alike.
Dóra Petrányi
Hall of fameCMS
Next Generation Partners
Junior partners with significant recognition from clients and peers in the market and key roles on multiple matters.
Katalin Horváth
CMS

Practice head

The lawyer(s) leading their teams.

Dóra Petrányi

Other key lawyers

Katalin Horváth, Márton Domokos, Péter Homoki