When someone dies leaving assets, family or connections in more than one country, the first and most important question is not who inherits — it is which country's law decides who inherits. Across most of the European Union, a single regulation now answers that question, and the answer is often not the one families expect.
If you are a foreigner living in an EU country, own a holiday home abroad, or have heirs scattered across borders, your estate is "cross-border" whether or not you think of it that way. The rules that follow are general background to help you understand the landscape; they are not advice on your own estate, and the way they apply depends heavily on the exact countries and assets involved.
Why "which law applies" is the real question
Every country has its own succession law, and they differ profoundly. Some give the surviving spouse a large share; others favour children. Many continental European systems reserve fixed portions of an estate for close family — so-called forced heirship — which a will cannot override. Common-law systems such as those in England, Ireland and much of the United States generally allow far greater freedom to leave assets to whomever you choose. The same will can therefore produce completely different outcomes depending on which national law governs it.
For decades, this created confusion: a German court might apply one law, a French court another, and a person's estate could be split into pieces each governed by a different system. The EU Succession Regulation — often called Brussels IV — was designed to bring order to this by ensuring that, in principle, one single law governs the whole of a person's succession.
The default rule: habitual residence
Under the regulation, the default is that the law of the country where you were habitually resident at the time of death governs your entire estate — both movable assets such as bank accounts and investments, and immovable assets such as real estate, wherever they are located. This is a major shift for many people, who assume their own nationality's law will apply, or that property is always governed by the law of the country where it sits.
Habitual residence is not the same as where you are registered, where you pay tax, or where you hold citizenship. It is a factual assessment of where your life is genuinely centred — your home, your family, your social and economic ties, and how long and how settled your presence has been. For someone who has clearly retired abroad and built a life there, it may be straightforward. For a person who divides time between countries, keeps a home in their country of origin, or has only recently moved, it can be genuinely uncertain — and that uncertainty is exactly where disputes arise.
Choosing the law of your nationality
The regulation gives you an important option: you may choose the law of a country of your nationality to govern your succession, instead of the law of your habitual residence. If you hold more than one nationality, you may choose the law of any of them. This choice must be made expressly, normally in a will or a similar declaration, and it is one of the most powerful planning tools available to anyone with cross-border connections.
This matters because it lets you bring predictability to your estate. An expatriate who wants the testamentary freedom of their home common-law system, or who wants to ensure their children receive reserved shares under their national law, can lock in that outcome rather than leaving it to depend on where they happen to be living when they die. Without such a choice, a later move abroad could silently change the law that governs everything.
Which countries are covered — and which are not
The regulation applies in most EU member states, but not all. Critically, Ireland and Denmark do not take part, and the United Kingdom did not opt in. That means estates connected to those countries are not governed by the regulation in the same way, and their own private international law rules apply instead — which can still point to the law of nationality, the location of property, or domicile, depending on the country.
This produces important traps. A choice of law that is recognised in a participating state may not be treated the same way by a non-participating one, and assets located outside the EU — or in countries that apply their own mandatory rules to local real estate — may be handled differently regardless of what your will says. Cross-border planning therefore has to account for every country where you have assets, not just the one where you live.
Tax is a separate question
One of the most common and costly misunderstandings is to assume that the law governing your succession also governs the tax. It does not. The regulation deals only with civil succession — who inherits and how the estate is administered. Inheritance and estate taxation is governed entirely separately by each country's domestic tax law and by any bilateral tax treaties.
As a result, more than one country may claim the right to tax the same estate, sometimes leading to double taxation that can only be relieved, if at all, through treaties or domestic credits. The country whose law decides who inherits may be different from the country that taxes the inheritance — and both can differ from the country where the heirs live. Tax planning has to be done alongside, but separately from, succession planning.
The European Certificate of Succession
To make cross-border estates easier to administer, the regulation created the European Certificate of Succession (ECS). This is a document, issued by an authority in a participating state, that proves the status and powers of heirs, legatees, executors and administrators, and is recognised across the participating countries without further formalities. It allows an heir to demonstrate their entitlement to a bank or a land registry in another member state without re-litigating the question in each one.
The certificate does not replace national probate or inheritance documents entirely, and it has a limited period of validity, but it can significantly reduce the friction of dealing with assets spread across borders. Knowing whether and when to apply for one is part of administering a cross-border estate efficiently.
Getting it right
Cross-border succession is an area where small details — where you are habitually resident, whether you made an express choice of law, which countries your assets sit in, and how each one taxes the estate — can change who inherits and how much reaches them. The rules interact across multiple legal systems, and a will that works perfectly in one country can create unintended results in another. Because so much turns on your specific circumstances and the exact countries involved, the safest step when planning an estate or handling an inheritance that crosses borders is to speak with a qualified inheritance lawyer who can review your situation and coordinate advice across the relevant jurisdictions before you decide what to do.