Probably every country has formulated its inheritance law and family law so that it constitutes a fair and balanced overall solution for all concerned. This balance is put at risk when both German and foreign law applies in transnational cases. This is often the case in bi-national marriages.

Of course all legal systems have provisions that protect the rights of the surviving spouse. The concepts that apply, however, fundamentally differ.

The main problem results from the conflict between inheritance law and the matrimonial property law. Inheritance law determines who is entitled to what share of the estate of the deceased spouse, while matrimonial property law determines the financial relationship between the two spouses. Either inheritance law or matrimonial property law may provide a starting point for determining the rights of the surviving spouse.

German law seeks to find a solution primarily in the area of inheritance law. When one spouse dies, the rights of the surviving spouse to the common matrimonial property are honored in that he or she receives a share of the estate - usually one half - while the children each receive their share of the other half. The surviving spouse will generally not have any further claim under matrimonial property law.

In many other legal systems the situation is precisely reversed. In many cases this means that the surviving spouse has no claim whatsoever under inheritance law if the deceased spouse had children – in the legal systems of Scandinavia, for example. In countries where such a system applies, the rights of the spouse are protected by matrimonial property law. The common share in the marital property continues even after the death of one spouse. Thus the surviving spouse receives an appropriate share of the total estate even though he or she may not actually inherit.

Generally speaking, each of the situations described above and their combined forms are examples of balanced solutions. Problems only occur when various aspects of the same marriage are subject to different jurisdictions at the same time. Situations can arise, for example, where a surviving spouse is entitled both to the lawful share of the inheritance according to one jurisdiction and to a share of the property according to the other jurisdiction. This works to the disadvantage of any children. The reverse situation (found just as frequently in practice), where the surviving spouse has no legal claim to inherit under the applicable rules of one jurisdiction and has no claims to the matrimonial property under the applicable rules of the other jurisdiction, is even worse. In that case the surviving spouse ends up with nothing!

Every state has its own rules as to which law applies in international cases. Unfortunately what goes by the name of Private International Law is also regulated differently in different countries. This leads to conflicts, and the differences are indeed considerable.

In the case of inheritance law in many countries (including Germany) the nationality of the testator determines which national inheritance law applies. Many other legal systems focus on the last residence of the testator. However, often the last residence of the testator is the deciding factor only if the testator has lived there for a specific period of time.

The situation in respect of matrimonial property law is even more varied. Most countries refer in one way or another to the spouses' place of common residence, some to the first place of residence, others also taking later places of residence into account. In some countries the applicable law remains unchanged for the duration of the marriage, in others a change of jurisdiction may - after a certain transitional period – follow the change of place of common residence. And finally, many countries take the nationality of the husband as a reference point. This leads to special problems in Germany, because such a provision is regarded as discriminatory and is not recognized.

In this confusion it is obvious that a situation can easily arise in which the inheritance law of one country and the matrimonial property law of another apply simultaneously. This often has the consequences for the financial security of the surviving spouse mentioned above – often unforeseeable for those involved.

Conflicts of this nature typically occur in the first few years of the marriage or in connection with a move to another country. Under certain circumstances the applicable laws of both jurisdictions may fail to offer any lasting protection. Depending on the extent to which the various legal systems conflict with one another, the consequences are substantially divergent and can lead to unpleasant surprises in matters concerning both inheritance and divorce.

A move to another country can also have a substantial impact - usually unintended by either spouse – and can make a difference as to which country's matrimonial property law applies. For example, if one spouse has received property by inheritance, the other spouse is not entitled to any share of this under German matrimonial property law. Many other legal systems allow the surviving spouse a share of one half. In Germany, unlike other countries, the surviving spouse is basically not entitled to any property of the deceased spouse that existed before the marriage. It is clear that an amendment to the relevant legislation in this case can mean a sudden and significant change in the marital property situation.

It can even lead to the absurd situation where the applicable law ultimately depends on the country in which legal proceedings are instituted in the case of a dispute.

In the situation described above it is for all intents and purposes a matter of chance as to whether and to what extent the surviving spouse will be financially secure should his or her spouse die. This makes it impossible to take sensible measures for the disposition of assets. Here, proper financial security can only be achieved on the basis of appropriate planning, both with regard to the death of a spouse and the outcome of a divorce.

The surviving spouse's inheritance rights can be set down in a will. A married couple can resolve the question of mutual claims by means of a matrimonial property agreement. Even the question which law shall apply can to a certain extent be regulated in a will or a matrimonial property agreement.

The contents of either a will or a matrimonial property agreement must be in accordance with the jurisdictions involved and, from a purely formal point of view, must be phrased in such a manner that they are acceptable to judges in both countries.