EU mandatory disclosure rules, known as DAC6 (Directive (EU) 2018/822), oblige intermediaries such as tax advisers, accountants, banks and lawyers to report cross-border arrangements with defined hallmarks to the tax authorities, in the Netherlands the Dutch Tax Administration (Belastingdienst). The main exception: a lawyer bound by legal professional privilege is exempt, and the duty then passes to other intermediaries or to the client. This article does not deal with the fiscal merits of any arrangement, which is outside our practice; it deals with who carries the obligation, what happens if it is missed, and how it interacts with confidentiality.

Table of contents

What triggers the reporting duty?

A cross-border arrangement becomes reportable when it shows one of the hallmarks listed in the annex to the directive. Examples are a confidentiality clause about the tax advantage, a fee linked to the tax advantage obtained, or the use of a loss-making company to reduce tax. Whether an arrangement qualifies is a legal assessment; record it with reasons when the arrangement is designed, because the 30-day reporting period leaves little room to reconstruct it later.

Who has to report?

The intermediary who designs, markets, organises or makes available the arrangement, or who assists in implementing it, reports first. Where several intermediaries are involved, each must report unless it can show that another has already filed the same information with the Belastingdienst. Keep evidence of who filed and when, rather than assuming it.

When does the duty shift to the client?

When no intermediary is obliged to report, for example because the only intermediary is a privileged lawyer or is established outside the EU, the taxpayer must report. Disputes between adviser and client usually start here: the client discovers the duty late, while the 30-day period has already started to run.

What if legal professional privilege applies?

A lawyer bound by privilege (verschoningsrecht) is exempt from reporting. In Orde van Vlaamse Balies (case C-694/20, 8 December 2022), the Court of Justice of the EU held that requiring such a lawyer to notify other intermediaries of their reporting duty infringes the confidentiality of lawyer-client communications under Article 7 of the EU Charter of Fundamental Rights. The lawyer must still inform the client (the taxpayer) that the reporting duty now rests with them.

In a 2024 judgment the Court added that this protection only covers practising lawyers. Tax advisers and other professionals cannot rely on it, even where national law allows them to represent clients.

What happens if you do not report?

The Belastingdienst can impose an administrative fine, and in serious cases the Public Prosecution Service (Openbaar Ministerie) can prosecute under fiscal criminal law. There is also civil exposure: an adviser who failed to report, or failed to tell the client that the duty had shifted, may be liable to the client under Article 7:401 of the Dutch Civil Code (BW) for the fine the client then incurs.

What should you check as an adviser?

Have you assessed, in writing, whether the arrangement shows a hallmark?
Do you know which other intermediaries are involved and who files?
Do you keep proof that another intermediary has filed, if you rely on it?
If you are a lawyer relying on privilege, have you informed your client in writing that the duty has passed to them?
Does your engagement letter allocate assessment, filing and information duties?

What should you check as a client?

Has your adviser told you whether the arrangement is reportable?
Has your adviser confirmed in writing who files and when?
If your only adviser is a privileged lawyer or is established outside the EU, are you ready to file yourself within 30 days?
Have you supplied the information your adviser needs in time?

What can we do for you with DAC6 reporting duties?

Our corporate lawyers advise on the legal side of the obligation; for the fiscal assessment of an arrangement we work alongside a tax specialist. We can:

Draft the clauses in your engagement letter that allocate reporting and notification duties.
Assess whether legal professional privilege applies to your role.
Advise an adviser or a client on liability after a missed filing.
Act in a dispute between adviser and client about who should have filed.

Summary

DAC6 requires intermediaries to report cross-border arrangements with defined hallmarks, within 30 days.
If no intermediary is obliged to report, or the only one is a privileged lawyer, the duty shifts to the taxpayer.
Since C-694/20, a privileged lawyer need not notify other intermediaries, but must inform the client; tax advisers cannot rely on this privilege.
A missed filing can lead to a fine, fiscal criminal exposure and civil liability toward the client.