International Law

Public and private sector entities involved in transnational business activity seek advice and representation from Paxus on matters arising under international law. We regularly advise on dispute resolution between foreign investors and host States, or between two or more States. We design winning strategies to address the complex and far-reaching effects on global business activity of public and private international law, and cross-border regulation and enforcement initiatives.

Common Issues


We advise and represent clients with respect to various bodies of public international law, including:

  • International Investment Law
  • International Human Rights Law
  • International Humanitarian Law
  • International Criminal Law
  • International Environmental Law
  • Climate Change Law
  • Indigenous Peoples Law
  • International Labour Law
  • Refugee and Internally Displaced Persons Law
  • International State Responsibility
  • Public international law in domestic courts

We also advise on issues arising under international law, including:

  • Investment protection
  • State sovereignty and succession
  • Privileges and immunities
  • Treaty negotiation and interpretation
  • Territorial and boundary disputes
  • State-State disputes
  • Human rights and business
  • Litigation under regional human rights conventions
  • Sovereign debt and defaults
  • Cross-border infrastructure, energy and mining projects
  • International organizations and treaty bodies
  • Conflict of laws
  • International contracting
  • Economic sanctions, import & export controls

Team Experience Highlights


  • Advising a European power company invested elsewhere in Europe on investment protection and structuring under investment treaties and the ECHR.
  • Advising an Asian mining company in relation to investment protection and ESG risks in several countries in Latin America.
  • Advising a British artificial intelligence company on international and comparative law relevant to its business.
  • Advising an American multinational technology conglomerate on conflicting domestic and international standards on freedom of expression, and on investment protection.
  • Advising a Spanish infrastructure company on investment protection in relation to the construction and maintenance of water infrastructure in a West-African country.


  • Advising a US headquartered international financial institution on the immunities of another international organisation headquartered in a West African country and its assets.
  • Advising a British investment fund on investment treaty arbitration award annulment and enforcement proceedings.
  • Advising a European engineering company on an unresolved territorial dispute, international law with respect to occupation and indigenous peoples’ rights.
  • Advising an American mining company on maritime boundary delimitations and proceedings before the PCA and ITLOS.
  • Advising an American beverage company on proceedings against a Latin American State before the Inter-American Court of Human Rights.


  • Advising a Latin American State on international investment law in connection with the drafting of its National Action Plan to implement the UNGPs.
  • Advising a European telecommunications company and separately an Asian energy company on international law considerations in respect of investments in Myanmar.
  • Advising a European gold mining company on international law issues in relation to its investment in a disputed and conflict affected territory in the Caucasus.
  • Providing training on international and comparative law to lawyers in Colombia through the IBA, ANDI and CCB and dispute resolution to government lawyers through the East Africa Law Society.
  • Advising delegations from OAS Member States throughout the drafting of a human rights treaty at the United Nations.

Also see Business & Human Rights practice

Dispute resolution

  • Representing States and investors in many investment treaty arbitrations (see Investment Arbitration practice).
  • Representing private entities in several transnational tort litigations involving international law in the UK, US and Canada (see BHR practice).
  • Representing a US oil drilling services company in litigation in the US against Venezuela under the FSIA expropriation exception.
  • Representing a Latin American State in an investment treaty arbitration and advising it on related proceedings against it before the Inter-American human rights system and against the investor before courts in the US.
  • Representing a State in its participation in The Philippines v. China arbitration concerning the South China Sea brought under Annex VII of UNCLOS.

Dispute resolution

  • Representing Mexico against the US before the ICJ in Avena and Other Mexican Nationals concerning the Vienna Convention on Consular Relations.
  • Representing a Latin American State in the preparation of a claim against an Asian State before the ICJ under the try or extradite provision of the Convention Against Torture.
  • Representing a journalist in a petition before the UN Human Rights Committee against a Latin American State.
  • Representing a former government minister in a petition before the Inter-American Commission on Human Rights against a Latin American State.
  • Representing 35 women in a petition to the CEDAW Committee against an East African State.

Also see International Arbitration practice

Recognised leaders in the field

Our specialised academic and professional experience ranks us among leading public international lawyers. Where we really stand out is in our combination of international relations and international law background with commercial awareness and experience.

Read our thought leadership

“Recognised for her expertise on public international law with notable experience in international dispute resolution”

Chambers Global 2021

Suzanne Spears “handles advisory and contentious work, with a focus on matters related to investment treaties, territorial boundaries, international trade and sovereign immunity.”

Legal 500 UK: Public International Law 2019

“She has given us very practical and business-oriented advice, coming up with a very creative solution for us.”

Chambers UK: Public International Law 2022