ELZABURU Team Back to team Linkedin Partner Patent Area fjs@elzaburu.es Francisco Javier Sáez European Patent Attorney specialized in chemical patents As a chemist specialized in industrial property, Francisco Javier Sáez is a European Patent Attorney and deputy director of the Patent Area. Throughout his 25-year professional career, he has advised companies on the protection of inventions, with a special focus on the drafting, prosecution, and defense of patent applications in Spain, Europe, the PCT, and other international jurisdictions. He also frequently acts in oppositions before the European Patent Office, acting both as opponent and defender. He is involved in prior art searches, patentability reports, infringement risk analysis, and patent portfolio evaluations, primarily in the chemical, pharmaceutical, energy, environmental, and agrochemical industries. Teaching activity He has participated in preparation courses for the European Qualifying Examination and is a regular speaker at seminars, master's courses and conferences related to patents. Education: Graduate in Chemistry and specialized in analytical chemistry from the Autonomous University of Madrid. University Diploma «Contentieux des brevets in Europe» from the University of Strasbourg-CEIPI. Industrial Property Agent. European Trademark Agent. European Patent Attorney. European Patent Litigator (authorised representative before the Unified Patent Court) Practice areas Advice, registration and defence in the areas of: Patents and utility models «Francisco Sáez is heralded as an excellent practitioner with expertise in three distinct fields: chemistry, pharmaceuticals and mechanics. He is highly diligent and hardworking, and his ability to secure patents at a rapid pace is unparalleled. His communication with clients is exemplary, and this contributes to the exceptional quality of his work. Truly, Francisco's dedication and efficiency are beyond commendable» IAM Patent 1000 Associations of which he is a member EPI (where he has been a member of its “Council” for 15 years), UNION-IP (Member of the «Patents Commission»), AIPPI, FICPI. Languages: Spanish, English (Technical Translator). Recognitions: The Legal 500, IAM Patent 1000, WIPR leaders, Leaders League (Best patent registration offices in Spain), Best Lawyers in Spain. Francisco Javier Sáez Partner Patent Department fjs@elzaburu.es Membership associations EPI, UNION-IP, APPI Languages ​​Spanish, English (Technical translator) Length of service at the firm 2000 Experience Specialist in the drafting, prosecution and defence of all types of patent applications before the various patent offices, particularly Spanish, European and PCT patents, as well as in various foreign countries, mainly in the chemical field. He is also responsible for advising applicants on matters such as prior art searches, preparation of patentability reports, infringement risk reports, and patent portfolio assessment, among others. Ten years as a Researcher and Project Manager in the R&D Department of an important multinational company manufacturing electrochemical batteries. Regular collaborator in preparation courses for the "European Qualifying Examination" and in seminars and master's degrees related to patents. Member of the “Patents Commission” of UNION-IP. Chemist Training (Analytical Chemistry Specialty) (Autonomous University of Madrid). Licensed Industrial Property Agent since 2004. European Patent Attorney since 2006. European Trademark Agent since 2004 (Authorized representative before the European Union Intellectual Property Office (EUIPO). European Patent Litigator. University Diploma “Patent Litigation in Europe” (University of Strasbourg-CEIPI). Practice areas Patents. PI Strategy. Surveillance. R&D and technology transfer. Renewables. Pharmacy. Industrial. Research: Universities and Technology Centers. Latest publications and appearances by the professional ELZABURU: 35 professionals referenced in the 18th Edition of Best Lawyers in Spain November 13, 2025 / ELZABURU, the only Spanish firm at the top of the Leaders League 2025 ranking as one of the best law firms… July 17, 2025 / ELZABURU, recognized once again in the IAM Patent 1000 ranking for its excellence in patents June 10, 2025 / See all posts

Meet our partner Luis Baz, attorney and director of the trademark practice, specializing in trademark, domain name, and copyright rights.

Meet our partner Enrique Armijo, a lawyer specializing in all types of legal proceedings for the defense of IP rights.

Meet our partner Luis Beneyto, a trademark attorney and expert in domain name recovery procedures (UDRP).

ELZABURU Team Back to Linkedin Team Honorary Partner ac@elzaburu.es Antonio Castán After more than 35 years of litigation experience in industrial and intellectual property and 25 years as a Partner at Elzaburu, we appoint Antonio Castán as Honorary Partner, in recognition of his career and his contribution to the development of the litigation area. His professional career, always focused on the exercise of judicial actions in industrial and intellectual property, has been marked by success. Throughout these decades, he and his team have been involved in highly relevant proceedings for rights holders in very diverse fields, from characters and works of popular culture, such as Tarzan or The Simpsons, to international brands or literary authors such as Chesterton, as well as sports personalities such as Zinedine Zidane. In addition, he has participated in complex litigation before Spanish courts in matters such as copyright, trademarks or patents. Antonio was also a Professor at the Pontifical University of Comillas and the author of numerous publications. Among them are the books Plagiarism and other studies of intellectual property, Intellectual Property and also, Poetry, Patents in the digital ecosystem and other studies on industrial property, Albert Camus in the light of copyright and, in 2026, Borges in the light of copyright. Although he held prominent positions in national and international rankings of the legal profession, Antonio has always pointed out that his greatest source of pride has been the team of lawyers who joined the ELZABURU Legal Department and to whom he sought to impart an example of dedication to customer service, loyalty to adversaries, procedural good faith, and intellectual and personal humility. As he himself wrote: “In industrial and intellectual property there is always more to learn than you can teach.” Education: Bachelor of Laws from the Pontifical University of Comillas (ICADE, Madrid). Collegiate in 1985, Madrid. “Antonio Castán is a well-regarded name in the IP field, particularly in relation to the defense of patent rights. Castán also maintains a reputation for his copyright knowledge. "Antonio Castán has experience, expertise and seniority." Chambers Global Associations of which he is a member ALADDA (ALAI), ASEDA Languages ​​Spanish, English Awards Throughout his career Antonio Castán has received awards, tributes and recognitions from various publications, associations or directories. Among them are the DENAE Awards, AAAML (Association of Former Students of the Lucentinus Teacher Training College) and ADEPI (Association for the Development of Intellectual Property). Furthermore, it recently received in 2025 the AIPPI: a tribute book with 35 articles written on Intellectual Property by lawyers and professors who are experts in the field. Antonio Castán Linkedin Honorary Partner ac@elzaburu.es Associations of which he is a member AIPPI, ALADDA (ALAI), INTA Languages ​​Spanish, English Seniority in the firm 1997 Education Lawyer (Pontifical University Comillas – ICADE, Madrid). Collegiate in 1985, Madrid. Practice areas Patents. Industrial designs. Copyright and image rights. Brands and trade names. Litigation, arbitration, mediation. IP Media & Entertainment. Publishing sector. Experience After 37 years of litigation in industrial and intellectual property, the last 25 as a Partner at ELZABURU SLP, Antonio Castán has had to retire from the legal profession due to an irreversible eye problem. Our Firm decided to name him “Honorary Partner”, in recognition of his career, so that he can maintain a symbolic and testimonial bond with us, with clients and with his professional colleagues. His professional career, always focused on the exercise of judicial actions in industrial and intellectual property, has been marked by success. Antonio has defended such endearing characters as Tarzan, Lex Luthor and The Simpsons in court, but also writers like Chesterton or celebrities like Zinedine Zidane. He obtained for JACK DANIEL'S the first ruling from the Spanish Supreme Court on community exhaustion of trademark rights in a case of parallel imports and judicially guaranteed in Spain the position of the American beer brand BUDWEISER against the Czech company in the well-known international conflict. . In a case of pharmaceutical patent infringement for some French laboratories, the preliminary proceedings and the judicial action undertaken gave rise to compensation of 8 million Dollars. Antonio was a Professor at the Universidad Pontificia Comillas and author of many publications, including three books titled “Plagiarism and other intellectual property studies”, “Intellectual Property and also Poetry” and “Patents in the digital ecosystem and other studies”. on industrial property”. Although he always held leadership positions in national and international law rankings, Antonio only felt proud of the team of lawyers who joined the Legal Department of ELZABURU SLP (currently 25) and to whom he always tried to transmit an example of vocation. of customer service, loyalty to adversaries, procedural good faith and intellectual and personal humility. As he wrote: “In industrial and intellectual property, there is always more to learn than you can teach.” Latest publications and appearances by the professional: Again, Leading Firm in the Leaders League Ranking 2022 July 11, 2022 / REUS Legal Debate Forum: The Trade Secrets Act (Reus), Madrid February 21, 2019 / Industrial Property in the Digital Ecosystem January 1, 2019 / See all posts

Meet our partner Ignacio Diez de Rivera Elzaburu, director of operations and expert in digital transformation and innovation.

Meet our Managing Partner, Mabel Klimt. She's responsible for the Legal and Media & Entertainment business areas.

Meet our President and Partner, Alfonso Diez de Rivera Elzaburu. He is a lawyer and industrial property agent.