Tax and customs law affects the day-to-day and strategic decisions of businesses and executives: corporate taxation, VAT, reporting obligations, audits, disputes, and cross-border trade issues (customs duties, classification, origin, customs value and formalities). Sion Avocat helps you anticipate, secure and defend your position with a clear, pragmatic approach.
Understanding tax and customs law
In practice, these topics are not only technical: they directly impact your cash flow, your strategic decisions (investments, structuring, transactions), and your risk exposure in the event of an audit.
Expertise focused on the needs of businesses and executives
Yaël Sion LAWYERS & ASSOCIATES provides support in tax and customs law for businesses, executives, individuals and healthcare professionals. Depending on the matter, the support may focus on:
- advice (clarifying a rule, securing a decision, structuring a transaction),
- prevention (compliance, documentation, best practices),
- defence (tax audit, adjustments, negotiation, litigation).
Our key areas
in tax and customs law
To make navigation easier, this page introduces our three main sub-areas. Each topic has its own dedicated page if you want to go further.
Tax disputes & reassessments
When the tax authorities challenge a return, issue an adjustment proposal or apply penalties, timing and strategy become decisive. The objective is to understand the case, respond in a structured way, and protect your rights at every stage.
Tax audit
A tax audit is not just a request for documents: it is a process governed by rules, deadlines and evidence issues. With the right support of a tax audit lawyer, this can be managed more calmly: framing communication, preparing supporting documents, analysing sensitive points, responding to the authorities and anticipating next steps.
Our approach:
clarify, secure, defend
In tax and customs matters, results often depend on method:
Clarify
understand your situation, your objectives, risk points and realistic options.
Secure
document, formalise and align economic reality with documents and filings.
Defend
when necessary, build a response strategy and manage the matter with the authorities.
Go further
To explore the topics in more detail, please consult the dedicated pages above. If you have an urgent question or need quick guidance, you can also choose an online consultation (video call or written advice).
FAQ – Tax & Customs Law
What is the difference between a tax audit and a tax reassessment?
The tax audit is the verification phase (requests, review, exchanges). A reassessment occurs when positions are challenged and adjustments are formally notified. Effective support starts early, from the very first exchanges.
When should I consult a tax lawyer?
As early as possible for high-stakes issues: a sensitive transaction, uncertainty about a filing, a letter from the authorities, or an announced audit. Anticipation often reduces risk and stress later.
Is customs law only relevant for large groups?
No. As soon as a business imports or exports (even occasionally), customs issues may arise (duties, classification, origin, formalities). A good reflex is to secure the framework early, especially when amounts become significant.
Can I get support for a single specific issue?
Yes. Support can be targeted (analysis, review, response strategy, audit framing) or broader, depending on your needs and timing.
