Who we are
KSI Attorneys-at-law LLC is a boutique tax firm founded by Kevin Sirman, a Franco-Swiss attorney-at-law with
10 years of experience in international tax law, registered at the Geneva and Paris Bar Associations. Before founding the firm, he practiced at a leading French energy group, two of the world's foremost tax advisory firms, and a Geneva-based law firm serving international private clients.
Our practice is built around a simple conviction: complex international situations deserve senior-level attention, not commoditised advice. Every client works directly with experienced counsel. We operate from Geneva, Paris, and São Paulo, advising clients across Europe, the Americas, and beyond, in English, French, Portuguese, and conversational Russian.
10 years of experience in international tax law
4 languages — English, French, Portuguese, Russian
3 offices — Geneva, Paris, São Paulo
Specialized expertise where it matters most
US tax law
Navigating US tax obligations across borders
US citizens and green card holders are taxed on their worldwide income, regardless of where they live. For Americans residing in Switzerland, this creates a layer of complexity that most advisors are ill-equipped to handle.
We advise US-connected clients on the full spectrum of their cross-border obligations: FBAR and FATCA reporting, treatment of foreign accounts and investment structures, as well as the coordination of US and local tax liabilities under applicable tax treaties.
Whether you are relocating, restructuring, or simply seeking to bring your situation into compliance, we provide practical, legally certain solutions — without unnecessary exposure.
Brazilian tax law
Deep expertise in Swiss-Brazilian tax matters
Brazil's tax system is among the most complex in the world, and its interaction with Swiss and French rules creates situations that require genuine specialist knowledge — not generalist advice.
We assist clients with ties to Brazil in navigating the Switzerland-Brazil tax treaty, the social security convention, and the specific rules governing the taxation of Brazilian-sourced income and assets held abroad.
From structuring holding arrangements to advising on succession and wealth planning across both jurisdictions, we deliver tailored solutions that reflect the legal realities of both systems.
Relocation to Switzerland
A stable foundation for your life, your family, and your wealth
In a world of shifting regulations and political uncertainty, Switzerland stands apart, offering a legal and institutional framework built over decades to last.
Political stability
A direct democracy and federal structure built on consensus, not abrupt political cycles, giving residents confidence that today's rules will still hold tomorrow.
Economic strength
A resilient economy, a strong currency, and a banking sector built on discretion and prudence, a natural base for preserving wealth across generations.
Fiscal predictability
A transparent, negotiable tax framework, including the lump-sum taxation regime for qualifying foreign nationals, backed by an extensive treaty network, enabling genuine long-term planning.
Legal certainty
Exceptional safety and strong legal protection of private property, administered by an efficient, incorruptible public administration.
We assist high-net-worth individuals and entrepreneurs at every stage: assessing eligibility for residence permits and lump-sum taxation, structuring the transfer of assets, and ensuring long-term compliance.
A well-prepared relocation is not just a change of address — it is a strategic decision.
What we do
Tax Litigation
We represent clients in complex disputes before Swiss and French tax authorities, from administrative challenges to court proceedings. We defend against assessments, contest residency determinations, and leverage treaty protections to minimize exposure.
Tax Advising
We advise on international tax planning, cross-border structuring, and private wealth organization — including lump-sum taxation negotiations, holding structures, and the coordination of tax exposure across multiple jurisdictions.
Corporate Law
We assist entrepreneurs and investors with company formation and governance, from Swiss SA/AG structures to international holding arrangements, ensuring seamless cross-border establishment and long-term compliance.
Immigration law
We advise high-net-worth individuals and entrepreneurs on Swiss residence permits, work authorizations, and lump-sum taxation regimes — streamlining the path to tax-efficient relocation for investors and professionals.
Frequently Asked Questions
Death and taxes are certain. But we will handle the second ones.
Contact
Whether you have a specific question or simply want to explore whether we can help, we welcome an initial conversation. All exchanges are strictly confidential.
Geneva - Switzerland
35, rue des Bains
1205 Geneva
Paris - France
87, boulevard Malesherbes
75008 Paris
São Paulo - Brazil
205, Rua Olimpíadas, Vila Olímpia
São Paulo - SP, 04551-000
+41 78 626 58 78
+33 642 53 60 37
Affiliations
