Westenberg Advokatur & Mediation


As my client, you will have control over the scope and content of my work. During an initial telephone call, I will happily discuss the various options available to you and which one makes the most sense for you.


I will analyse the legal background for you and make recommendations on how to proceed. It goes without saying that I will also support you in finding amicable out-of-court solutions.

Litigation and representation

Often, there is no alternative but to let the court decide on a conflict. In these cases, I represent your interests before the Swiss courts and authorities.

Mediation/Collaborative law

As a trained mediator, I will support you in a structured process to find a joint, co-operative solution to the conflict. The aim is to develop a forward-looking, viable solution in a joint dialogue on an independent basis.

As a collaborative lawyer, I support you as your lawyer in a CLP procedure. In this procedure, all parties to the conflict involve a specially trained collaborative lawyer. Together, an out-of-court and viable solution is worked out.

Expert opinions

On behalf of or for foreign courts or lawyers, I prepare independent expert opinions on a defined cross-border issue.

Key points

Private international law

Many of my current customers are subject to private international law, mostly international family law. These include:

  • Litigation before Swiss courts for international cases (e.g., for foreign real estate, dividing pension assets or other financial assets in Switzerland for divorces that take place abroad)
  • Pre-litigation consulting
  • Place of jurisdiction, applicable law
  • Acknowledging and enforcing foreign rulings in Switzerland
  • Independent expert opinions on behalf of or for foreign courts or lawyers

My expertise is based on many years of practical work and a solid academic framework thanks to my doctoral thesis in private international law with Prof. Dr. Frank Vischer as well my publications in legal commentaries and papers. For many years I represented Switzerland as an expert at the Hague Conference on Private International Law. I am supported by a global network of specialized lawyers globally, and I am a member of the International Academy of Family Lawyers.

Family law in Switzerland

Family law with legal separations and legal divorce is another specialisation of mine. Over 35 years of experience in consulting and litigation work set me apart when it comes to complex and comprehensive asset allocations among spouses (shareholdings, real estate, custody accounts, etc.). I often use my supplementary business education (MBA) when dealing with legal corporate constructs.

Furthermore, I advise spouses on their marriage and inheritance contracts.

Consulting for family businesses

I advise family businesses and SMEs in business matters, particularly regarding corporate law (legal structures, shareholder agreements). If necessary and after prior review, I may join Board of Directors. Besides my experience in negotiations, I am backed by my MBA and relevant publications in company law and in international commercial law.

About me

Westenberg Advokatur & Mediation

Dr. iur. Catherine Westenberg
Attorney at Law and mediator SAV, MBA

Enrolled in the city of Basel’s Bar Register of Attorneys.

Languages: German, English, French

For 35 years I have been practising as a lawyer in North-western Switzerland and have acquired profound expertise in international and national law. I work as a consultant for my clients, litigate before Swiss courts and authorities, and offer mediations and other procedures for settling disputes out of court.

Work History


Owner of Westenberg Advokatur & Mediation, Basel, Switzerland

2019 – 2023

Partner at Liatowitsch & Partner, Basel, Switzerland

2010 – 2019

Owner of the law firm WestenbergPartner, Basel/Liestal

1990 – 2010

Partner at various law firms in Switzerland

1986 – 1989

Various internships as a lawyer in court, at various law offices and at the cantonal tax authority



Collaborative Lawyer, clp Schweiz


Mediator training at IEF Zürich (recognized as SAV mediator in 2007)


Master of Business Administration (MBA), City University, Seattle


Obtained Ph.D, Dr. iur. University of Basel (Thesis: Citizenship in Swiss private international law)


Bar exam (Canton of Basel-Country), Admission to the bar


lic.iur. University of Basel, Faculty of Law

Practical work

  • I have been practising as an independent lawyer since 1990 and have served on various Boards of Directors
  • I have been working as a mediator since 2007
  • 2011 – 2023 Head of the Specialist Group for Mediation at the bar association in Basel
  • 2013 – 2022 Member of the Expert’s Group on Recognition and Enforcement of Agreements reached in Course of Family Matters Involving Children, Represented Switzerland at the Hague Conference on Private International Law, the Hague/NL



Commented on Articles 20/21/22 and 24 IPRG [Swiss Federal Act on Private International Law]; Basel comment on Swiss private law, international private law; published by Grolimund/Loacker/Schnyder, Basel, 4th edition 2020


Internationale güterrechtliche Verhältnisse aus Schweizer Sicht [International marital assets from the Swiss perspective], in FamPra 2016, pg. 123 ff. (together with Gabrielle Bodenschatz)


Commented on articles 20/21/22 and 24 IPRG [Swiss Federal Act on Private International Law]; Basel commentary on Swiss private international law, Private international law; Published by Honsell/Vogt/Schnyder/Berti, Basel, Switzerland, 3rd edition 2012


Commented on articles 20/21/22 and 24 IPRG [Swiss Federal Act on Private International Law]; Basel commentary on Swiss private international law, Private international law; Published by Honsell/Vogt/Schnyder/Berti, Basel, Switzerland, 2nd edition 2007


Unlauterer Wettbewerb [Unfair competition] (together with David Vasella), in: Handbuch des Internationalen Wirtschaftsrechts [manual of international business law]; Otto Schmidt publishing company, Cologne, Germany, 2001


Aktienrecht [Company law]: by Büren / Walter Stoffel / Anton K. Schnyder / Catherine Christen-Westenberg; Schulthess publishing company, Zurich, Switzerland, 2001


Commented on articles 20/21/22 and 24 IPRG [Swiss Federal Act on Private International Law]; Basel commentary on Swiss private international law, Private international law, published by /Vogt/Schnyder/Berti, Basel, Switzerland, 1st edition 1996


Staatsangehörigkeit im schweizerischen Internationalen Privatrecht [citizenship in Swiss private international law]; Schweizer Studien zum internationalen Recht [Swiss studies on private international law)], Schulthess publishing house, Zurich, Switzerland, 1992



Ausländische Liegenschaften im internationalen Güter- und Erbrecht [Foreign properties in international matrimonial regimes and inheritance law]: Schulthess Forum Ehegüterrecht [matrimonial property law], Zurich and Bern, Switzerland


Eine Schweizer Sicht zur Mediation und zu ADR im Kindesschutz und Familienrecht im grenzüberschreitenden Kontext [A Swiss perspective on mediation and on ADR in child protection and family law in an international context]: Deutsch-Englischsprachige Richtertagung [German/English-language meeting of magistrates], Vienna, Austria


Anerkenn- und vollstreckbare Entscheidungen nach Haager Übereinkommen über die zivilrechtlichen Aspekte von internationalen Kindsentführungen (HKÜ) [recognized and enforceable decisions according to the Hague Convention on the Civil Aspects of International Child Abduction]: Bundesamt für Justiz [Federal Office of Justice], Bern, Netzwerk von Fachpersonen BG-KKE [network of specialists, Swiss Federal Act on International Child Abduction and the Hague Conventions on the Protection of Childs and Adults]


Internationale güterrechtliche Verhältnisse aus Schweizer Sicht: Fachgruppe Güter- und Erbrecht der Advokatenkammer Basel [international marital property from the Swiss perspective: Specialist group for marital property and inheritance law of the Basel Bar Association] (together with Gabrielle Bodenschatz)

Tenures in Boards of Directors and Executive Boards

  • President of the Cura Familia Association, the supervisory board of Heime Auf Berg AG, Seltisberg, Switzerland
  • Member of the Board of Directors at Gysin Tiefbau AG, Hölstein, Switzerland
  • Member of the Board of Directors at Gysin Immobilien AG, Hölstein, Switzerland


Westenberg Advokatur & Mediation

Innere Margarethenstrasse 5 (5th floor)
P.O. box 138
CH-4010 Basel, Switzerland

Tel. +41 61 336 90 30


How to reach us

By tram

Tram lines 6, 10, and 16 to the stop at Heuwaage
Tram lines 1, 2, 8 and 16 up to the stop at Markthalle
Both tramway stops are only a 3-minute walk away from out office.

By train

The office can be reached by foot from the main SBB train station in 5 minutes.

By car

The public Elisabethen car park is located in the immediate vicinity.