Jonas Kiefer is specialised in Food Law and Unfair Competition Law. He advises and represents clients in the food and consumer goods industry as well as in the associated retail sector. His practice focusses on examining advertising concepts and marketing campaigns, advising on product labelling and packaging, and litigating for his clients in Unfair Competition Law and Food Law disputes. He has special expertise in Price Indication Law (esp. German PAngV) as well as in Food Information Law (esp. EU Food Information Regulation) and in the field of geographical indications. Another main focus is the protection of trade secrets (esp. German GeschGehG).

Jonas Kiefer joined CMS in 2019. In 2021 and 2023, he was seconded to the legal departments of a large German brewery group and a large German confectionery manufacturer.