Charles Heisbourg
Partner
Charles is an M&A lawyer by trade, having spent the first years of his career in the corporate team of Luxembourg’s premier business law firm. He then moved on as first general counsel of a major Luxembourg commercial group, setting up the legal function, and heading group HR and general services. He pursued with managing one of the group’s major businesses and net profit contributors, doubling size during his tenure.
With an entrepreneurial drive, Charles founded 55LEGAL in 2024 with a view of providing high quality legal advice geered by managerial experience and a hands-on approach.
Charles is a board member/observer in RE and PE companies and a member of major business and industry bodies.
- Academics
Charles is a graduate in law from ULB, Belgium (Ms Private Law) and LSE, UK (LLM Corporate and Securites Law). He was admitted to the Luxembourg Bar in 2012 and has lectured companies’ law at University of Luxembourg until 2018.
- languages
Advice in English, French, German and Luxembourgish.
Charles Duro
Partner
Charles is a tax and corporate lawyer with relevant expertise in private equity tax structuring, FATCA/CRS compliance, M&A tax strategies and tax litigation. Over the years, he has honed his ability to design sophisticated tax structures and implement them seamlessly, providing clients with both strategic insights and practical execution.
After five years with the tax team of a Magic Circle firm, Charles followed his career in a boutique corporate law practice, where he further developed his skills in navigating complex legal and tax frameworks with a pragmatic and hands-on approach.
An avid advocate for knowledge-sharing, Charles regularly intervenes at universities, delivers workshops, and publishes articles on cutting edge legal and tax topics. His interests also extend to innovative fields such as IoT and DLT, with regular advice to start-ups on these topics.
Charles is an active member of the Luxembourg Bar as well as the AIJA (Association Internationale des Jeunes Avocats).
His reputation in the field is underscored by his recognition as one of the top 100 key lawyers in Luxembourg and among the top 10 tax lawyers in the country (Paperjam 2022).
Charles joined 55LEGAL in 2025.
- Academics
Charles graduated from law school in Aix-en-Provence, obtaining a master’s degree in corporate engineering (Ingénierie des sociétés) as well as a corporate jurist diploma (DJCE). He also obtained a LLM in International Taxation from King’s College London.
Charles was admitted to the Luxembourg Bar in 2017.
- languages
Advice in English, French, German and Luxembourgish.
Bob Calmes
Partner
Bob’s practice revolves around mergers and acquisitions, and corporate law advice (including corporate aspects of public M&A). He is notably advising private equity firms, financial sponsors, multinationals and startups on downstream acquisition finance and structuring, VC funding, corporate governance. He is furthermore a trusted advisor to Luxembourg operational businesses and entrepreneurs.
Bob was a partner and has practiced for 19 years with the largest Luxembourg law firm, notably heading the New York representative office from 2013 to 2017. He is co-chair of the ABA European Deal Point Study, IBA officer (Space Law Committee). Bob has been ranked as a “Leading Individual” for “Commercial, Corporate and M&A” by Legal500. He has been a member of the Luxembourg Bar since 2006.
- Academics
Bob holds a master in international law from the Université Paris I Panthéon-Sorbonne, a degree from the Institut d’Administration de Entreprises (Université Paris I Panthéon Sorbonne) as well as a Master of Laws degree (LL.M.) from Pace Law School.
- languages
Advice in English, French, German and Luxembourgish.