Guillaume has been a member of the Paris Bar since 2022. He advises companies, executives and investors in strategic disputes, both at the pre-litigation stage and before the civil and commercial courts.

His practice includes shareholder disputes, corporate litigation, commercial and contractual disputes, as well as liability claims relating to financial and accounting disclosures.

Before joining Almain in 2026, Guillaume practised at a firm specialising in international arbitration, and subsequently at firms active in business litigation and financial markets disputes.