International law is important in business and corporate matters, in asset protection, and in ensuring security for your family. Today, borders are increasingly blurred in both personal relationships and investments.
For this reason, it is essential to understand international treaties, European Union regulations, supranational rules, and conflict resolution mechanisms. An improper application of International Law can lead to financial losses, legal uncertainty, and even the loss of opportunities.
Our goal as specialists in International Law is to explain these regulations clearly and to offer tailored solutions for each client.
International Law is the body of rules, principles, treaties, and customs that govern legal relations. Although it originally focused on interactions between States, it now also encompasses the activities of international organizations such as the United Nations (UN) or the World Trade Organization (WTO), the obligations of multinational companies, and the protection of individuals’ fundamental rights.
Thanks to this evolution, International Law now affects not only States but also investors, entrepreneurs, expatriates, and individuals who conduct their personal or professional lives across multiple jurisdictions.
International Law is divided into two main branches: Public International Law and Private International Law. Both operate in different spheres, and understanding which one applies is essential for making the right decisions.
Public International Law governs the legal relations between States and International Organizations. Its scope covers international treaties, security, human rights, environmental protection, and diplomatic relations.
Practical example: A free trade agreement between the European Union and Mercosur that eliminates tariffs and non-tariff barriers, allowing products to become more competitive in that market.
It directly affects, for instance, investments made by a company in a foreign country that are protected under a bilateral investment treaty signed between both States, or fundamental rights, which are safeguarded by the Universal Declaration of Human Rights and other international covenants.
Private International Law deals with legal relationships between private parties (either individuals or legal entities) that involve a cross-border element. Its purpose is to resolve conflicts that involve more than one jurisdiction: Which courts have jurisdiction? (International Judicial Competence), which law applies to the substance of the matter? (Applicable Law), and how can judgments or arbitral awards be recognized and enforced (exequatur)?
Practical example: Determining which national law applies to a divorce between a Portuguese spouse and a French spouse residing in Germany, and which court has jurisdiction to handle the case.
It is highly relevant because it defines the rules on which courts are competent in the event of a breach of an international contract, which law governs the validity of that contract, and where or how to enforce one’s rights in other jurisdictions.
At Arthur & Marin, we specialize in all areas covered by International Law that affect both companies and individuals. Below are some of our main practice areas:
An international contract provides legal certainty and helps anticipate risks across different legal systems. We support our clients from negotiation to execution at the international level.
Our services include:
For companies seeking to expand into other countries, International Law plays a key role in regulating international growth. We offer comprehensive advice on foreign investments to ensure safe, well-supported decisions.
We advise you on your international business through:
The resolution of international disputes requires a deep understanding of procedural rules, negotiation, and the operation of different jurisdictions.
Our services include:
We represent our clients in arbitration proceedings before the world’s leading arbitral institutions, such as the International Chamber of Commerce (ICC) in Paris and the London Court of International Arbitration (LCIA). We assist clients from the drafting of the request for arbitration to representation at hearings and enforcement of the award.
We provide guidance and support in situations involving divorce, child custody disputes, and international inheritance matters, always with the utmost discretion, empathy, and efficiency.
Companies with international operations are subject to various national and supranational regulations depending on their industry. Failing to comply with international regulatory law (such as sustainability directives, GDPR, greenwashing rules, or due diligence requirements) can result in multimillion-euro fines and serious reputational damage.
Public International Law is the branch of law that governs relations between States, international organizations, and other actors within the international community. We represent and advise individuals, companies, public entities, international institutions, and national authorities. Our main areas of practice in Public International Law focus on the following:
1. Protection of human rights before international courts
We advise and represent victims of violations of fundamental rights before bodies such as the European Court of Human Rights (ECHR), the UN Human Rights Committee, and the Court of Justice of the European Union (CJEU).
We prepare applications, appeals, and written submissions based on the European Convention on Human Rights, the International Covenant on Civil and Political Rights, and other human rights protection treaties. We defend the principle of effective judicial protection in all proceedings.
2. Diplomatic and consular immunity
We analyze the scope, limits, and exceptions of diplomatic immunity in civil, criminal, and labor proceedings. We defend the rights of individuals affected by abuses of diplomatic status and represent States or institutions in proceedings involving the discussion of immunity prerogatives.
3.International investment disputes and arbitration
We represent both investors and States in investment dispute proceedings before institutions such as the ICSID (International Centre for Settlement of Investment Disputes), UNCITRAL (United Nations Commission on International Trade Law), and other international arbitral bodies.
We provide legal advice on the interpretation and application of Bilateral Investment Treaties (BITs), multilateral investment protection agreements, and arbitration clauses in international contracts, as well as on restrictive regulatory measures and cross-border contractual disputes.
4.Compliance with international treaties and conventions
We assist companies, individuals, and public entities in fulfilling obligations derived from international treaties in the areas of trade, environmental protection, judicial cooperation, and investment protection.
We advise on the interpretation of multilateral conventions (such as the Paris Agreement on climate change or WTO treaties) and bilateral agreements, ensuring that international operations are conducted in full compliance with international law.
We also represent clients in monitoring and compliance proceedings before international bodies and specialized tribunals.
International Law draws upon various interconnected sources, such as:
These are, by far, the most important source of International Law. A treaty is a written agreement between States (or between a State and an international organization) that creates legally binding obligations for the parties. Treaties can be bilateral (between two countries) or multilateral (among multiple countries).
The Vienna Convention on the Law of Treaties governs how treaties are drafted, interpreted, and amended. The Vienna Convention on the International Sale of Goods (CISG) is an example of a treaty that harmonizes rules governing sales contracts.
Before treaties existed, custom was the main source of law. For a practice to become a binding customary rule, two conditions must be met:
These are fundamental legal principles recognized by the main legal systems of the world. Their function is to fill legal gaps and ensure that a court is never unable to render a judgment due to the absence of an applicable rule.
They include universal concepts such as the principle of good faith, the prohibition of abuse of rights, the principle of res judicata (final judgment), which prevents a case already resolved from being retried, and the principle that every breach of an obligation entails the duty to make reparation.
Strictly speaking, these are not law-making sources, but they play an essential role in interpreting and determining existing rules.
Decisions of international courts, such as the International Court of Justice (ICJ), help clarify and interpret legal norms.
As for doctrine, the opinions and writings of legal scholars contribute to the interpretation and systematization of International Law.
It depends on the type of contract and the clauses agreed upon by the parties. In general, Private International Law determines which legislation applies according to criteria such as the place of performance of the contract, the residence of the parties, or the intention expressed in the agreement itself.
Yes, but the procedure varies depending on the country. Within the European Union, judgments are automatically recognized thanks to Regulation (EU) No 1215/2012 (Brussels I bis). In third countries, recognition depends on bilateral treaties or Private International Law procedures (exequatur).
International Law protects businesses through investment treaties, double taxation agreements, and trade agreements. These instruments ensure legal certainty, protection against expropriation, and dispute resolution mechanisms.
International arbitration is an alternative dispute resolution method in which the parties choose independent arbitrators to settle their disputes outside the courts. Arbitral awards are enforceable in over 160 countries thanks to the 1958 New York Convention.
Public International Law governs relations between States and international organizations (such as the UN or the EU), while Private International Law applies to relationships between individuals or companies from different countries.
A breach may lead to a claim for damages under the applicable law. The injured party may bring the case before competent courts or an arbitral tribunal, depending on the provisions of the contract.
The European Union acts as a subject of International Law, with the capacity to conclude treaties and represent its Member States in areas under its competence, such as foreign trade or the common fisheries policy. It also facilitates mutual recognition of judicial decisions among Member States.
You should file a complaint with the competent national authorities or with international bodies such as the European Court of Human Rights (ECHR) or the UN Human Rights Committee, depending on the treaties ratified by the country concerned.
This depends on each country’s legal system. In most European States, ratified international treaties have higher authority than national laws. Therefore, in the event of a conflict, the treaty prevails.
A BIT is an agreement between two States that guarantees investors from each country fair and equitable treatment, protection against expropriation, and free transfer of capital. In case of a dispute, the investor may resort to international arbitration.
The EU General Data Protection Regulation (GDPR) restricts the transfer of personal data outside the European Economic Area (EEA). Such transfers are only permitted to countries offering an adequate level of protection or through the use of appropriate safeguards (such as standard contractual clauses or binding corporate rules).
International Law applies to real-life situations that affect companies, investors, and individuals. Below are real and successful examples that illustrate how this legal discipline operates in practice
A European company signed a supply contract with a distributor in Brazil. A breach occurred due to delivery delays. Thanks to the proper inclusion of international arbitration clauses and the selection of the competent forum, the dispute was resolved before the International Chamber of Commerce (ICC) in Paris. This avoided lengthy litigation in foreign courts and ensured the enforcement of the arbitral award in both jurisdictions.
This example demonstrates how Private International Law protects the parties’ interests and facilitates the enforcement of cross-border agreements.
In a divorce case between a Portuguese citizen and a French citizen residing in Germany, the correct application of Private International Law made it possible to determine which court had jurisdiction and which law applied to the division of assets and child custody.
Our intervention ensured a fair and efficient resolution.
A French company decided to expand its business into Mexico. Before investing, an analysis was carried out of the network of Bilateral Investment Treaties (BITs) and applicable Free Trade Agreements (FTAs).
Thanks to this planning, the company obtained guarantees regarding profit repatriation and arbitration mechanisms in case of disputes, ensuring that its investment was protected against regulatory risks.
A European company exporting machinery to South Africa was unaware of the preferential origin requirements set out in the trade agreements between the EU and that country.
With proper advice in International Law and foreign trade, the certificates of origin were reviewed and the tariff exemptions were correctly applied, avoiding fines and customs delays.
A Spanish tech startup developed patentable software and sought to expand into the U.S. and Japan.
The correct application of International Law and Intellectual Property Law allowed the company to register patents in multiple jurisdictions, draft international licensing agreements, and protect its innovation from copying or misuse.
A French citizen passed away leaving assets in Spain, Belgium, and Luxembourg.
Thanks to careful estate planning and the application of Regulation (EU) No 650/2012 on international successions, it was possible to determine the applicable law, manage taxes correctly, and distribute the inheritance efficiently among the heirs — avoiding legal disputes between jurisdictions and reducing the overall tax burden.
A multinational company based in Germany was required to comply with Directive (EU) 2019/1937 on internal whistleblowing channels and U.S. anti-corruption laws.
Through the correct implementation of international compliance programs, the company successfully avoided financial penalties and safeguarded its corporate reputation — demonstrating how International Law plays a vital role for companies with cross-border operations.
Nowadays, it is common for an individual or a company to require the recognition in Belgium of a judgment rendered abroad. Whether it concerns a
Companies operating in several markets, foreign investors, or even individuals engaged in cross-border relations need legal certainty beyond their own borders. Nowadays, legal decisions are
European regulation has a direct and increasing impact on businesses operating in France, both domestic and foreign. Whether it is a company involved in e-commerce,
On February 27, 2025, the Legislative Resolution of the European Parliament of March 13, 2024, which establishes the proposal for the new Union Customs Code
The Double taxation agreement (DTA) between Spain and Belgium is a treaty designed to prevent taxpayers from being taxed twice on the same income in
From the smallest clause in an export contract to the structure of a multimillion-euro investment, international rules define the framework. Understanding International Law is essential to protect your assets, your business, and your personal interests.
Maximize the security of your investments and international operations with the support of our International Law specialists at Arthur & Marin.
info@arthurmarin.com
+32 465 34 53 45
