KASTEL Patentanwälte – at the heart of Munich’s Patent District

The ancestry of the office founder Heinz Lesser can be traced back to Friedrich Christian Lesser (1692–1754), a distinguished theologian, historian, and the first chronicler of the city of Nordhausen. He published numerous scholarly works, became a member of the Leopoldina and the Prussian Academy of Sciences, and made significant contributions to the intellectual life of his time. To commemorate the 300th anniversary of his birth, the Friedrich Christian Lesser Foundation was established in 1992.

About 125 years after Lesser's death, the Imperial Patent Office (Kaiserliches Patentamt), the predecessor of today's German Patent and Trade Mark Office (GPTO), was founded in 1877. During this period, Heinz Lesser, a descendant of Friedrich Christian Lesser, was born in 1913.
 

The firm looks back on an eventful history. It was founded by Heinz Lesser (born 1913), a descendant of Friedrich Christian Lesser. 

After completing his engineering degree in Berlin, Heinz Lesser initially worked at the German Aviation Research Institute. With the founding of the Federal Republic of Germany, the reopening of the Patent Office gained momentum. 

On 12 August 1949, a ‘Law on the Establishment of a Patent Office’ came into force. Just a few months later, on 1 October 1949, the new German Patent Office began its work – but in Munich, a decision that was not without controversy at the time. The 423 staff members were initially based in the library wing of the Deutsches Museum. 

Heinz Lesser moved from Berlin to Munich and opened his patent attorney’s practice there in 1951. The firm’s origins thus date back to the early days of the German Patent and Trade Mark Office. The focus was initially on clients from Japan. Between 1951 and 1978, 768 patent families were created.
 

• In July 1978, Otto Flügel joined the law firm. The address was now ‘Lesser & Flügel’ at Cosimastraße 81 in Bogenhausen. 
• In March 1980, Heinz Lesser retired and was removed from the list of partners. However, his name remained associated with the firm for some time. 

The subsequent developments were as follows: 

• September 1988: “Lesser Flügel & Säger” at Cosimastraße 81.
• August 1989: Move to Richard-Strauß-Straße 56
• 1993: “Lesser & Flügel” at Wißmannstraße 14.
• 1999: Stefan Kastel joined as a partner the law firm “Lesser, Flügel & Kastel”.
• 2002: “Flügel Preissner Kastel”.
• 2003: Heinz Lesser dies shortly after his 90th birthday; Otto Flügel dies shortly afterwards.
• 2004: “Flügel Preissner Kastel Schober”, at Nymphenburger Straße 20.

Stefan Kastel founded Kastel Patentanwälte in 2016 with the aim of sharpening the firm’s specialist focus and providing even more efficient and personalised support to its growing client base. 

In 2016, as part of the spin-off, the firm moved to its current premises at St.-Cajetan-Straße 41 in the east of Munich, near the Werksviertel district. 

The Smart-House building is characterised by innovative architecture, sustainability, energy efficiency and an appealing mix of uses, including offices, retail, catering and a nursery. 

Shortly afterwards, Bernhard Surrer joined the firm as a partner, expanding its areas of expertise to include, amongst other things, machine learning and software patents. 

With a constantly expanding team of associate attorneys and highly skilled patent assistants with many years’ experience, the firm is renowned for providing specialised and highly personalised support to discerning international industrial clients.

In the spring of 2026, the firm celebrated a double anniversary. We looked back with gratitude on 10 years of Kastel Patentanwälte and 75 years since the firm’s foundation.

With cheerful and competent people, the firm’s team is looking forward to the coming years and decades. We look optimistically towards an exciting future, one that will be shaped by new inventions, and in which we, for our part, will have the privilege of supporting innovations.