A few months ago, my brother called to tell me that he and his girlfriend were going to get PACSed, as they say in Luxembourg – in other words, they were looking to get a civil partnership. I was happy for them, of course, but surprised by how long it took me to find the right response.
Congratulations seemed appropriate. Still, I realised that I could not have explained with any confidence what, beyond the tax return, a PACS would actually change.
I knew what marriage was supposed to mean, both socially and legally. A civil partnership was less clear.
Like many people, I had absorbed the vague idea that it was marriage made lighter: fewer formalities, an easier exit, and no need to develop strong opinions about table arrangements.
No. It creates genuine rights and obligations, but it does not reproduce all the protections that come with marriage.
PACSed partners must provide each other with material assistance, may be jointly responsible for ordinary household debts, and receive protection in relation to their shared home. A civil partnership can also bring tax, employment, and social-security benefits.
The difference is rarely obvious on the day the papers are signed. It appears later, when a partner dies, property has to be divided, or a document issued abroad must be recognised by a Luxembourg institution.
Court judgments have a habit of turning grief into dates, percentages, and procedural history.
Behind a 2016 judgment from Luxembourg's Constitutional Court was a fairly simple human story: somebody had lost their partner and then discovered that the law placed them in a different category from a surviving spouse.
The deceased had made a will naming the surviving partner as a beneficiary. The couple had also registered a PACS, but their partnership had lasted less than three years and they had no common descendants.
Under the inheritance tax rules applicable when the estate opened in 2012, the survivor faced a basic rate of 15%. At the time, a surviving spouse in the same position benefited from a rate of 5%, regardless of how long the marriage had lasted.
The surviving partner challenged the distinction, arguing that it was incompatible with the constitutional principle of equality.
The Constitutional Court disagreed. In its view, spouses and civil partners were not in sufficiently comparable legal situations.
Its reasoning turned on one essential difference. A surviving spouse is an heir under Luxembourg law. A PACSed partner is not and will inherit only if the deceased has made a valid will in their favour.
The court was not deciding that one relationship was more loving or committed than the other. It was applying the legal consequences attached to two different statuses.
That may sound abstract until the distinction determines what happens to someone's home and savings after their partner dies.
The tax position has improved since the case was decided. Inheritances between spouses are now exempt from inheritance tax. Civil partners receive the same exemption if their PACS was registered at least three years before the estate opened.
If that period has not elapsed, the survivor may face the 15% basic rate applicable between unrelated people, with possible increases depending on the value inherited.
Reaching the three-year mark changes the potential tax bill. It does not write the will. Without a valid will, a PACSed partner has no automatic claim to the estate.
The deceased's property instead passes under the ordinary order of succession, potentially to children, parents, siblings, or more distant relatives. This remains true even if the couple lived together for decades and regarded everything they owned as part of the same shared life.
Inheritance rights and inheritance tax are therefore separate questions. The exemption can make an enormous difference once a civil partner inherits, but it cannot create an inheritance where none exists.
A will is especially important for couples in civil partnerships, although it cannot override the reserved inheritance rights of the deceased's children. Couples with children from earlier relationships, property abroad, or several nationalities may need more careful estate planning.
In such cases, a romantic faith in common sense is unlikely to survive first contact with succession law.
Marriage does not automatically make everything common, but it does automatically place the couple under a matrimonial property regime. Unless the spouses choose another regime through a marriage contract, Luxembourg's statutory community regime applies.
Under that regime, salaries, income generated by property, and assets bought during the marriage generally become common property. Assets owned before the marriage, as well as gifts and inheritances received by one spouse, generally remain personal.
Couples who prefer to keep their finances separate can choose separation of property through a notarial contract.
A PACS begins from the opposite assumption. Each partner keeps their earnings and owns the assets they can prove belong to them.
Property acquired by one partner during the PACS generally remains theirs. If neither person can establish sole ownership of an asset, it is presumed to belong to both in equal shares.
The rule is clear enough on paper. Relationships are rarely organised with the same precision.
One partner may pay for groceries, utilities, holidays, and the hundreds of ordinary expenses that disappear as soon as they are paid. The other may put money into investments or property held in their own name.
One person may reduce their working hours, relocate, or take on more unpaid responsibilities at home.
The couple may see all of those choices as contributions to the same life. If the relationship ends, however, one person may hold the assets while the other holds a collection of receipts for things that have already been eaten, used, or enjoyed.
That does not make the PACS rules inherently unfair.
It means that ownership and contribution are not always the same thing and the law is much better at recording the first. It keeps excellent track of title deeds and rather poor track of who repeatedly took the afternoon off to wait for the plumber.
Civil partners can draw up a property agreement, buy assets jointly, and record the shares in which they own them.
The purpose is not to prepare for failure. It is to avoid relying on two people having exactly the same memory of an unwritten arrangement several years later.
This becomes particularly important because a civil partnership in Luxembourg is easier to end than a marriage. The partners may terminate it together, or one may do so alone after completing the required notification and declaration.
There is no divorce.
That simplicity is a genuine advantage for couples who do not want the heavier structure of marriage. It also means that ending a PACS does not automatically bring the same formal examination of the couple's finances.
Mutual financial support generally ends with the partnership, and a judge may order maintenance only in exceptional circumstances.
A divorce is hardly a guarantee of a painless or perfectly equal outcome. It does, however, place the division of the matrimonial regime and any claim for maintenance within a formal legal process.
After a PACS, property belonging to one partner does not become shared simply because the other made sacrifices that helped them acquire it.
A second court case concerns a problem particularly familiar in Luxembourg: a relationship recognised in one country meeting an institution in another.
Two French nationals living in France had entered into a French PACS. One partner had been insured through Luxembourg's pension system.
After that partner died, the survivor applied for a Luxembourg survivor's pension.
The application was refused because the French civil partnership had never been entered into Luxembourg's Civil Register. The surviving partner challenged the decision, but the Court of Cassation upheld the refusal in 2021.
There was no suggestion that the French PACS was invalid. The problem was that it had not been made legally enforceable against third parties in Luxembourg.
Lawyers describe this by saying that the partnership was not 'opposable' to the Luxembourg institution, a phrase almost impressively unsuited to explaining anything to someone outside the legal profession.
In practical terms, the pension authority was not required to recognise the partnership for the purpose of granting a survivor’s pension.
The couple had a relationship recognised by French law, but they had not completed the Luxembourg formality needed to rely on that status against the Luxembourg social-security institution. By the time the omission came to light, one partner had died and the missing registration could no longer secure the pension being claimed.
Current official guidance provides a procedure through which qualifying partnerships registered abroad can be entered in Luxembourg’s Civil Register.
Registration allows the foreign partnership to produce the same Luxembourg tax, social-security, and employment-law benefits as a partnership registered here.
The case does not mean that every foreign PACS is ineffective in Luxembourg. It means that couples should not assume recognition will happen automatically simply because the partnership is valid elsewhere.
Bureaucracy is at its most unforgiving when everybody thought the paperwork had already been dealt with.
For PACSed couples, the first question is whether each partner has made a valid will. They should also understand who owns the home, savings, investments, and significant purchases, rather than relying on an informal arrangement that may be difficult to prove later.
Couples who entered into a partnership abroad should check whether it needs to be recorded in Luxembourg. Those with children from earlier relationships, a business, substantial assets, or connections to several countries should consider individual advice from a notary, lawyer, or tax specialist.
Married couples should not assume that the word 'marriage' answers every financial question either. They should understand the matrimonial regime that applies to them and, if its rules do not suit their circumstances, consider whether a marriage contract is appropriate.
Nobody needs to respond to happy relationship news by demanding an inventory of the couple's assets. That would be an efficient way to stop receiving happy relationship news.
The couple themselves should nevertheless understand what their chosen status will do if one of them dies or the relationship ends. These are not cheerful questions, but the law is full of issues that are easiest to discuss while they still feel theoretical.
My uncertainty when my brother called had nothing to do with whether his relationship deserved to be celebrated. Of course it did. What surprised me was how easily I had treated a familiar word as though its legal meaning must be equally familiar.
Getting PACSed is worth celebrating. It is also worth understanding, preferably before a court, tax authority, or pension fund is asked to explain what it means.
