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Julien Lemonnier Jean

Jean-Julien Lemonnier

Partner - Head of Ethics, Investigations, Defence, Avocat a la Cour

Jean-Julien Lemonnier is a partner within the Ethics, Investigations, Defence practice and heads the Antitrust practice at Stephenson Harwood in Paris.

D +33 1 44 15 80 78 M +33 6 61 76 74 57

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Awards and Recognition

"Jean-Julien Lemonnier is always accessible and highly adaptable. His pragmatic and insightful advice consistently reflects a deep understanding of legal complexities as well as the broader economic context."

"Jean-Julien Lemonnier is an outstanding antitrust lawyer, combining deep legal expertise with a strong commercial perspective. He is highly strategic, precise, and communicates complex issues with clarity."

"Jean-Julien Lemonnier's long-standing experience in merger filings, along with his collaborative approach, makes him exceptionally reliable and a pleasure to work with. He consistently adds value to every transaction and sets a high standard in the field."

The Legal 500 EMEA 2026 - EU, Competition & Distribution

Biography

He regularly advises companies on investigations into alleged anti-competitive practices, mainly initiated by the French competition authority or the European Commission, as well as on the implementation of compliance programs, and assisting clients involved in EU and multijurisdictional merger control filings.

He is also regularly involved in internal investigations, advising not only on the competition aspects but also on the potential criminal liability issues, in particular white collar.

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NEWS AND INSIGHTS

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Paris

Olivier Dorgans joins Stephenson Harwood as Partner

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Finance

Stephenson Harwood advises Apollo-managed funds on Hav Energy acquisition

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Paris

Stephenson Harwood receives trio of recognitions at Trophées du Droit awards

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Competition Litigation

End of antitrust exemption for liner shipping consortia: what will be the consequences for future cooperation between carriers?

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Dubai

Whistleblowing in the financial services sector – A global perspective

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Competition

Digital Decade: Digital Markets Act and Digital Markets, Competition and Consumer Bill

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Restructuring & Insolvency

Stephenson Harwood advises Circet on Scopelec Group takeover out of receivership proceedings

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