Bertrand Mariaux Avocats is a boutique law firm with a special expertise in impact entrepreneurship law.



Bertrand Mariaux Avocats works with asset management structures, investment funds and enterprises having an intentional & positive impact on society as well as for the social & solidarity economy.




The firm is born from a dual passion for law and positive social impact. BMA works with a passionate team of five lawyers registered at the Luxembourg and Paris law societies (barreaux de Luxembourg et de Paris). The firm acquired experience from top tier international UK, American, Dutch and French law firms, and trained at prestigious law and business schools around the world.




Due to its experience and unique character, the firm provides a wide variety of legal services advising in investment funds, corporate & tax law as well as in dispute resolution and it advises in all aspects surrounding impact investing and social economy law in Luxembourg and France.

Bertrand Mariaux Avocats advises in simple and complex commercial, financial structuring (company formations, mergers & acquisitions), social business (sustainable business, green business), corporations (corporate social responsibility - CSR), traditional and social banking (green finance, social finance, responsible finance, microfinance), investment funds (private equity funds, hedge funds), securitisation with a commercial or social purpose, and in social impact investment funds (environmental, social & governance - ESG, socially responsible investment - SRI, social venture capital).

The firm closely works with the social economy sector (social enterprises, agrément sociétés d’impact sociétal - SIS, agrément entreprises solidaires d’utilité sociale - ESUS, cooperative companies, charities), philanthropy (foundations) and nonprofit organisations (associations sans but lucratif - ASBL, loi 1901).




The firm works with a variety of clients, both small and large, from established corporations, charities and social enterprises to innovative start-ups and high-profile individuals. Its clients are also national and international public or private institutions (NGOs, professional groups).


Bertrand Mariaux

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Bertrand Mariaux is a registered lawyer with the Luxembourg (Liste 1 - oath-taking, 2011) and Paris (oath-taking, 2010) law societies. He has an LL.M. (hons), is a Certified Expert in Microfinance and has studied social entrepreneurship and impact investing. Bertrand has been involved in social entrepreneurship and microfinance projects.



Before founding Bertrand Mariaux Avocats, Bertrand has gained skills and robust experience within top-tier international UK based "Magic Circle" law firms covering aspects including investment funds, mergers & acquisitions, corporate finance, capital markets, and regulatory matters. He also trained at a top-tier international French law firm in Paris.

In addition, Bertrand successfully managed all legal affairs within the Financial Risk Unit of the Risk Management Department at the European Investment Bank.

Recently, Bertrand gave a presentation before the Haut Conseil à la Vie Associative in Paris (a French Prime Minister office's institution dedicated to social economy) about the latest piece of Luxembourg legislation on Social Impact Company (Sociétés d'Impact Sociétal - SIS).

Among other social impact investing ventures, Bertrand has volunteered and worked on projects involved in scaling the microfinance operations of an NGO in Uganda.

He is also one of the founding members of the Institut Luxembourgeois de Médiation, a nonprofit alternative dispute resolution organisation.


Bertrand is a registered Lawyer in Luxembourg (2011) and France (2010). While studying at the bar School in Paris, he obtained an LL.M. with distinction from Bond University. 

Bertrand has also acquired experience, skills, and knowledge in impact investing, social entrepreneurship & business. He has studied with the University of Oxford and the Wharton School of the University of Pennsylvania and is a Certified Expert in International Microfinance from the Frankfurt School of Finance & Management.

While at the Paris Bar School Bertrand also founded a legal aid association in a disadvantaged Paris suburb which finally received the support of the Paris Law Society.


Internship Opportunity

Would you like to gain experience in a diverse, unique field of law, doing something that makes a difference in a demanding, rewarding (we encourage responsible initiative-taking and decision-making) yet flexible (it is possible to work for us via teleworking or on a part-time basis) and human environment?

If so, please email your CV and/or cover letter to and You may also get in touch with us through Instant Messaging platforms such as: Facebook Messenger on Bertrand Mariaux, personal account and/or on Linked In.

We look forward to working with you.

Bertrand Mariaux


Bertrand Mariaux Avocats

22, avenue de la Liberté

L-1930 Luxembourg

Grand-Duchy of Luxembourg


PO Box 1057

L-1010 Luxembourg

Grand-Duchy of Luxembourg

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