Guillaume Guérin

Counsel, Paris

Guillaume Guérin

Counsel, Paris

Guillaume Guérin is a counsel in the firm’s Paris office. His practice focuses on advising publicly listed and non-listed companies and their managers, investment funds, and financial institutions on a wide range of regulatory and compliance issues, investigations, and corporate transactions.

Guillaume has significant experience in investigation, control, and sanction proceedings before the French financial markets authority (AMF) and the Banking Authority (ACPR), as well as with matters requiring international cooperation with foreign regulators including the Securities and Exchange Commission (SEC) and with any subsequent judicial proceedings.

He also has extensive experience advising investors, publicly listed companies, and their managers on financial markets transactions and regulations, including public mergers and acquisitions, tender offers, initial public offerings (IPOs), the securities issuances, initial coin offerings (ICOs) as well as on corporate governance and financial communications matters.

Guillaume is regularly recognized by The Legal 500 in its stock market litigation category in France. He has also been recognized by Leaders League in the “Highly Recommended” category for compliance in France.

Prior to joining the firm, Guillaume was a senior associate in DLA Piper’s Paris office and an associate at Dentons (formerly Salans). Before that, he spent five years at the AMF in the Investigations department and the Legal Affairs department.

Guillaume holds an LL.M. from the University of Virginia School of Law and a Master of Laws (DJCE-DESS) in business law and taxation from the University Jean Moulin Lyon III.

Guillaume is fluent in French and English.

Guillaume Guérin is a counsel in the firm’s Paris office. His practice focuses on advising publicly listed and non-listed companies and their managers, investment…

Education

University of Virginia School of Law (LL.M., 2001); University Jean Moulin Lyon III (DJCE-DESS 2000)

Bar Admissions

Paris, New York State

Activities and Affiliations

Board Member, French Securities Lawyers Association (ADB)

Former Lecturer, University Paris Dauphine

Five of our Paris-based lawyers have been recognized in the 2025 edition of The Best Lawyers in France.

Johannes Jonas is recognized for corporate law. His practice focuses on cross-border transactions and investments, mergers and acquisitions, employment law, and general commercial law.

Angéline Duffour is recognized for labor and employment law. Her practice focuses on all aspects of employment law in a diverse range of industries (including hospitality and leisure, life sciences and health care, chemical industries, luxury, fashion and transportation).

Muriel Goldberg-Darmon is recognized for banking and finance law, financial institutions, mergers and acquisitions law, and regulatory practice. Her practice focuses on advising listed companies and their managers, investment funds, insurance companies, and financial institutions on a wide range of regulatory and compliance issues, investigations, and corporate transactions.

Franck Le Mentec is recognized for tax law. His practice focuses on cross-border taxation, both for multinational enterprises and private clients.

Guillaume Guérin is recognized for regulatory practice. His practice focuses on advising publicly listed and non-listed companies and their managers, investment funds, and financial institutions on a wide range of regulatory and compliance issues, investigations, and corporate transactions.

The Best Lawyers in France relies entirely on peer review to determine and recognize professional excellence.

Established in 2014, Cohen & Gresser’s Paris office provides comprehensive legal services for our clients, including advising on corporate, employment, tax, financial services, white collar defense, and litigation-related matters. Our Paris attorneys work closely with the lawyers in our other offices on cross-border transactions, investigations, and litigation, in order to provide superior service to French and international clients.

Cohen & Gresser is pleased to share that The Legal 500 Europe, Middle East and Africa (EMEA) 2024 edition has recognized the firm’s Paris office for excellence in Stock Market LitigationEmployment and Tax.

Partner Franck Le Mentec is one of only four lawyers in France recognized as a Leading Individual in Transfer Pricing and International Tax, and partner Muriel Goldberg-Darmon is one of only 16 lawyers in France recognized as a Leading Individual for Stock Market Litigation, encompassing AMF investigations and sanction proceedings.

The 2024 edition also recognized partner Angéline Duffour as a recommended lawyer for Employment, and counsel Guillaume Guérin as a recommended lawyer for Stock Market Litigation.

Established in 2014, Cohen & Gresser’s Paris office provides comprehensive legal services on corporate, employment, tax, financial services, white-collar defense, and litigation-related matters. Our Paris lawyers work closely with the lawyers in our U.S. and UK offices on cross-border transactions, investigations, and litigation, providing superior service to our French and international clients.

The Legal 500 EMEA guide provides annual researched coverage of over 80 countries and over 2,700 law firms. The research involves a detailed assessment of various factors, including work conducted by law firms over the past 12 months and historically, experience and depth of teams, and client feedback.

Cohen & Gresser is pleased to share that The Legal 500 Europe, Middle East & Africa (EMEA) has recognized the firm’s Paris office for excellence in Stock Market Litigation, Employment and Tax in its 2023 edition. Paris partner Muriel Goldberg-Darmon is one of only 17 attorneys in France designated as a Leading Individual for Stock Market Litigation (including AMF investigations and sanction proceedings), and Paris partner Franck Le Mentec is one of only 4 attorneys in France designated as a Leading Individual in Transfer Pricing & International Tax.

The 2023 edition also recognized Paris partner Loïc Henriot and counsel Guillaume Guérin as recommended lawyers for Stock Market Litigation, and partner Angéline Duffour and counsel Anna Milleret-Godet as recommended lawyers for Employment.

Established in 2014, Cohen & Gresser’s Paris office provides comprehensive legal services on corporate, employment, tax, financial services, white-collar defense, and litigation-related matters. Our 14 Paris attorneys work closely with the lawyers in our other offices on cross-border transactions, investigations, and litigation, in order to provide superior service to French and international clients.

The Legal 500 EMEA guide provides annual researched coverage of over 80 countries and over 2,700 law firms. The research involves a detailed assessment of various factors including work conducted by law firms over the past 12 months and historically; experience and depth of teams; and client feedback. These latest Legal 500 recognitions for nearly half our Paris office are a testament to the firm’s extensive capabilities in the international arena.

Cohen & Gresser’s Paris office has earned six practice rankings and 13 individual rankings in the 2022 Leaders League guide. Leaders League highlights the firm’s “experienced lawyers” and ability to handle complex, cross-border matters.

Leaders League is an independent research and rating agency that provides comprehensive rankings and in-depth analysis of law firms and lawyers. The rankings are based on extensive research by an experienced team of analysts.

Ranked Practice Areas:

• Marketing, communication & digital – Advertising law & marketing

• Media & entertainment – Fashion Law

Ranked Individuals:

Franck Le Mentec: Wealth management – Wealth tax: regulation and litigation; Tax law – LBO tax

Guillaume Guérin: Compliance – Compliance program

Johannes Jonas: Private Equity – Development capital transactions

Loïc Henriot: Dispute resolution – Litigation with regulators and for listed operations; Compliance – Compliance program; Compliance – International investigation and internal investigation; Dispute resolution – Banking & Finance Litigation; Dispute resolution – Commercial litigation; Labor & Employment – Criminal labor law; Dispute resolution – White collar crime

Muriel Goldberg-Darmon: Dispute resolution – Litigation with regulators and for listed operations; Compliance – Compliance program; Compliance – International investigation and internal investigation; Private Equity – Development capital transactions; Asset management – Asset management

Established in 2014, Cohen & Gresser’s Paris office provides comprehensive legal services for our clients, including advising on corporate, employment, tax, financial services, white collar defense, and litigation-related matters. Our Paris attorneys work closely with the lawyers in our other offices on cross-border transactions, investigations, and litigation, in order to provide superior service to French and international clients.

International law firm Cohen & Gresser is pleased to announce that its Paris office has once again been recognized in The Legal 500’s 2022 Europe, Middle East, and Africa (EMEA) guide for its work in five practice areas: Commercial Litigation, Employment, IT and Internet, Stock Market Litigation, and Tax. The Legal 500 recognizes practices that are “providing the most cutting edge and innovative advice to corporate counsel.” Clients recognized C&G for its “ability to synthesise, analyse and argue matters” and noted that the firm “has an extensive technical track record and is able to support French and foreign clients” on all types of issues. Two C&G lawyers received top-level rankings and have been recognized as “Leading Individuals” in their respective practice areas. The full list of C&G lawyers recognized in The Legal 500 2022 EMEA guide includes:  

Guillaume Guérin was featured in an article by Agefi-Dow Jones in which he discusses Vallourec’s (a multinational manufacturing company) contemplated share capital reduction and consolidation of shares.

Cohen & Gresser announces the expansion of its White Collar Defense & Regulation team in Paris. Partner Muriel Goldberg-Darmon and Guillaume Guérin will advise listed companies and their managers, investment funds, insurance companies, and financial institutions on a wide range of regulatory and compliance issues, investigations, and corporate transactions.
In their latest article for Finascope, Muriel Goldberg-Darmon, Guillaume Guérin, and Pierre Wolman discuss the impact of the June 2024 European directive on due diligence for French companies. The directive aims to prevent negative human rights and environmental impacts from large companies, their subsidiaries, and business partners. It expands the obligations established by the 2017 French law, lowering the employee threshold and introducing stricter penalties. This shift will likely lead to increased litigation, especially as a new regulatory authority will oversee compliance and impose fines for violations.

In this article for Finascope, Muriel Goldberg-Darmon, Guillaume Guérin, and Pierre Wolman analyze the press release issued on May 29, 2024 by the European Securities and Markets Authority (ESMA) concerning the best practices to be followed by listed companies in their exchanges with financial analysts prior to the publication of financial results. They also discuss the French Financial Markets Autority’s position on the subject.

In this article for Finascope, Muriel Goldberg-Darmon, Guillaume Guérin, and Pierre Wolman analyse a draft legislation, which intends to introduce the possibility for listed companies to issue shares with multiple voting rights at the time of their listing. In particular, they discuss the regime of those shares and the impact the draft legislation could have on the attractiveness of the Paris marketplace.

Dans cette chronique pour Finascope, Muriel Goldberg-Darmon, Guillaume Guérin, et Eleonore Messina abordent les modifications réglementaires, applicables à compter du 1er janvier 2024, étendant le champ d’application du contrôle des investissement étrangers en France.
In this article for Finascope, Muriel Goldberg-Darmon, Guillaume Guérin, and Eleonore Messina discuss the regulatory changes effective January 1, 2024, which extend the scope of foreign investment control in France.
In this article for Finascope, Muriel Goldberg-Darmon, Guillaume Guérin, and Pierre Wolman discuss the four new recommendations on financial advertising published by the French Professional Advertising Regulatory Authority in collaboration with the French Financial Markets Authority. They also discuss the new certificate of responsible influence in the financial sector.
In this article for Finascope, Muriel Goldberg-Darmon, Guillaume Guérin, and Pierre Wolman discuss how the implementation of the European CSRD (Corporate Sustainability Reporting Directive) in France will significantly strengthen companies’ sustainability reporting obligations and increase their litigation risks. In particular, they address the disputes that could arise from the French Financial Market Authority (AMF) or from investors.

In this article for Finascope, Muriel Goldberg-Darmon, Guillaume Guérin and Pierre Wolman discuss the new guidelines regarding the conduct of an internal anti-corruption investigation, published in March 2023 by the French Anti-Corruption Agency and the French Financial Prosecutor's Office. Muriel Goldberg-Darmon, Guillaume Guérin and Pierre Wolman also analyze the importance of the internal anti-corruption investigation in the context of the negotiation of a judicial public interest agreement (the equivalent of the Deferred Prosecution Agreement in the United States).

In this article for Finascope, Muriel Goldberg-Darmon, Guillaume Guérin and Pierre Wolman discuss the reinforcement by the French Financial markets authority of its policy with respect to dilutive financing transactions. In particular, they describe the new disclosure requirements for listed companies, namely the obligation to publish a press release and a warning in the event of a dilutive financing transaction concluded with an intermediary.
In this article for Finascope, Muriel Goldberg-Darmon, Guillaume Guérin, and Pierre Wolman discuss how the new Control Guidelines published by the French Anticorruption Authority (AFA) clarify the sequence of the control procedure and integrate the current practices of the AFA in terms of control.

In this bylined article for Finascope, Muriel Goldberg-Darmon, Guillaume Guérin, and Pierre Wolman discuss the main contributions of the guide published on 16 March 2022 by the Strategic Information and Economic Security Service (SISSE), the French Business Federation (MEDEF), and the French Association of Private Companies (AFEP). This guide offers companies a methodology for classifying their “sensitive” data following the reform of the French blocking statute.

In this article for Finascope, Muriel Goldberg-Darmon, Guillaume Guérin and Pierre Wolman discuss France’s new whistleblower protection framework, which follows the adoption of the European whistleblowing Directive of 2019. In particular, they analyze the changes made to the “Sapin 2” law adopted in France in 2016.

In this article for Actes Pratiques et Ingénierie Sociétaire, Muriel Goldberg-DarmonGuillaume Guérin, and Pierre Wolman summarize and explain the different steps of a SPAC from a French-law perspective. They also address the issue of public information that must be provided to the public. (Subscription required.)

In this article for Finascope, Muriel Goldberg-Darmon, Guillaume Guérin, and Pierre Wolman discuss the Autorité des Marchés Financiers (AMF's) modification of the Investigations Guidelines (Charte de l’enquête et du contrôle) regarding the right to remain silent. They also examine its articulation with a potential obstruction and/or cooperation with the AMF during an investigation.

 
Muriel Goldberg-Darmon and Guillaume Guérin discuss the 2020 recommendations made by the French AMF (France’s financial markets regulator) during the pandemic regarding the handling of financial communications for publicly traded companies. In this article, Muriel and Guillaume explore the lessons that public companies can learn from such recommendations.

Muriel Goldberg-Darmon discusses recent French rules which strengthen France’s control over foreign investment in French companies listed on Euronext Paris.

In this C&G client alert, Muriel Goldberg-Darmon, Guillaume Guérin, and Pierre Wolman discuss the implications of two recent French rules that are meant to strengthen France’s control over foreign investment.