Our Team


Marie-Avril Roux Steinkühler LL.M.

Certified Lawyer in intellectual property and new technologies law

Marie-Avril Roux is a seasoned IP lawyer with more than 20 years of experience in business and intellectual property, with focus on copyright, entertainment, media, new technologies and trademarks. After 15 years practice in Paris, she is now based in Berlin and further advises or litigate for her clients in France and Germany.

Her particularity: a specialized bi- and international IP practice in three languages, French, English and German.

Marie-Avril has been practicing in all areas of copyright and entertainment Law: publishing, music, cinema, television, radio, live performance, advertising, art, counterfeiting, plagiarism, sponsorship, patronage, privacy, image, advising producers, publishers, authors, artists and celebrities. She litigates in France and also in Germany. Her practice also includes the representation of creators and artists and the management of their rights.

The other focus of her practice is trademark protection. She advises international companies on their brands and new technologies. She manages and develops trademark portfolios in more than 70 countries, in addition to designs and domain names. She advises, drafts and negotiates license agreements, coexistence etc., provides representation before the French trademark office INPI, the German trademark office DPMA, the EUIPO, and the Court of Justice of the European Union. She practices also in Data privacy Law.

Her clients are mainly involved in publishing, production, fashion, food industry, finance mainly, and she counsels several NGOs.

She likes to support her clients in their projects and develop these projects with them, being flexible and inventive. Her first training at Sciences Po in commerce and finance, and then her experiences in mergers and acquisitions, gave her an operational approach and allowed her to support the establishment of French companies' activities in Germany. And as it is great to always improve and adapt, she has resumed her studies and is currently completing an LL. M. in IP German law at the Humboldt University in Berlin.

Foto: Lars Pillmann, Pillmann.com

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Quentin Dequiret LL.M.


Lawyer in intellectual property law, personal data and new technologies 

Quentin Dequiret joined MARS IP in early 2020. Admitted to the Paris Bar in 2017, he works with Marie-Avril in French, German and European Intellectual Property Law, Personal Data Protection and Business Law.

Determined and creative, he is always willing and motivated to find practical and reliable solutions in legal matters.

His first training was in Law, Economics and Management in a preparatory class in Montpellier, and then in Business Law, which gave him a solid general knowledge coupled with a pragmatic approach to law and the management of intangible assets by companies.

He continued his studies within the French-German/European program BerMüPa from 2013 to 2015 in Munich, becoming a European Union enthusiast. Quentin obtained an LL.M. in German and International Business Law from the University of Munich (LMU) and a Master 2 in European Business Law from the University of Paris II (Panthéon-Assas). After selecting Patent Law and Personal Data Protection Law as the subjects of his university theses, his interest quickly turned towards intellectual property.

With a professional experience in IP/IT in law firms as well as in companies in France and Germany, he moved to Berlin in 2018 and evolves in an international context.

Concerned about the protection of the most vulnerable and passionate about innovation, he is also developing a solution facilitating access and understanding of the law for these vulnerable groups. Highly involved in the associative sector, Quentin supports the development and strengthening of French-German relations.

His working languages are French, German and English.


Sebastian Sycha LL.M.


Of Counsel

Sebastian studied law at the FAU Erlangen-Nuremberg and started working in 2011  in an intellectual property-oriented law firm in Bavaria. In his capacity as clerk of the Higher Regional Court of Nuremberg, he concentrated on commercial law and spent part of his work as a legal clerk in an intellectual property business in the USA. In addition, he deepened his knowledge in the Master's programme "Immaterialgüterrecht und Medienrecht" (LL.M.) at HU Berlin, which he successfully completed in 2019. Sebastian  also successfully completed the specialist courses "Urheber- und Medienrecht" (Copyright and Media Law)  and "Gewerblicher Rechtsschutz” (Intellectual Property).


Since his admission as a lawyer in 2014, Sebastian has been advising and representing clients in the fields of copyright and media law as well as intellectual property law, out of court and in court. His work focuses on copyright infringements, licensing agreements,  press and public relations law and competition law.


Sebastian speaks German, English and French. In the law firm MARS-IP Sebastian is available as a independent cooperation partner for cross-border legal issues.


Foto: Glasow, glasow Fotografie, www.foto-glasow.de

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Susanne Klingenberg

Office manager, translator

After her international management studies including stays in France, the USA and Dubai and a thesis about Brand and Trademark Law in China, Susanne started her career in Sales in Dubai before returning to Berlin in 1999 and taking over the showroom of a fashion label with responsibility for the East German market.

Her interests shifting towards Controlling and Finance, she stepped in as Business Unit Operations Manager for a British project management company in Berlin in 2002, followed by a further reporting interface position in a project development company in 2007.

Susanne has been self-employed since 2009 in the field of company set-ups, process optimizations, administration and bookkeeping, contract management and translations. She joined MARS IP in 2016 with the responsibility of invoicing, bookkeeping preparations and general administration.