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

We have a strong pro bono practice. 

We also assist asylum seekers.

We believe in legal aid (assistance judiciaire). Legal aid is open in cases of modest or nonexistent income.



Bertrand Mariaux Avocats works with asset management structures, investment funds and enterprises (non-profit or commercial) 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 & solidarity 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 & solidarity 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).