Associé de Gide, Olivier Dauchez est spécialisé en droit fiscal français et international. Il a acquis une expertise particulière en matière de fiscalité des opérations de fusions-acquisitions, de restructurations d'entreprises, d’investissements immobiliers, de financements structurés et de financements de projets et d’actifs.

Il intervient également en matière de fiscalité des particuliers et assiste  fréquemment des clients personnes physiques ou sociétés dans le cadre de contentieux ou de contrôles fiscaux.

Régulièrement classé comme l’un des meilleurs avocats en droit fiscal par les principaux guides juridiques, Olivier Dauchez a été cité comme étant un avocat « remarquable » qui démontre « des compétences impressionnantes dans la gestion de stratégies de haut niveau » (Legal 500 EMEA 2017) et comme ayant une « connaissance très forte de toutes les questions fiscales » et « bien informé sur les tendances et les évolutions du marché » (Chambers Europe 2017). Olivier est également reconnu parmi les meilleurs spécialistes du droit fiscal par Best Lawyers in France depuis 2018 et par International Who's Who of Business Lawyers. Il est également cité dans le Tax Directors Handbook comme l’un des meilleurs avocats fiscalistes du monde et est considéré comme « incontournable » par la revue française Décideurs.

Olivier Dauchez est membre du Cercle des Fiscalistes.

Olivier Dauchez a participé aux séminaires suivants :

• Londres, 2021 - 10th IBA London Finance and Capital Markets Tax Conference: structured financing and distressed restructuring
• Paris, 2020 - IACF : Actualité de la jurisprudence fiscale internationale
• Paris, 2020 - Paris, 2018 - Entretiens du Conseil d'Etat en droit public économique : participation au débat sur le thème "La fiscalité internationale à réinventer ?"
• Munich, 2015 - ABA IFA IBA US Europe Annual tax planning : Co-chair of the panel on BEPS Update attendant Robert Stack from US IRS International Affairs 
• New York, 2013 - International Tax Institute : Cross-Border Debt Push-Downs in M&A Transactions : Selected Tax issues
• Paris Chartered Institute of Taxation/ IACF - International aspects of the new 3% CIT on distribution of profits : limited compatibility with international and EU law
• New York, 2012 - Bloomberg BNA U.S. International and Transfer Pricing Advisory Boards : "Withholding Tax on Dividends Paid to a CIV: Where Do We stand After the May 10, 2012 Santander Case ?"
• Paris, 2012 - IACF - animateur du  séminaire : Retenues à la source et crédits d'impôts à l'épreuve des engagements internationaux de la France ; Actualité de la fiscalité internationale 

« Olivier Dauchez is noted for his expertise in tax litigation, with further activity assisting with tax issues around corporate transactions. "He is very quick and goes deep into the analysis," claims one impressed source. »
Chambers Europe 2022-  Tax

« Olivier Dauchez is noted for his expertise in tax litigation, with further activity assisting with tax issues around corporate transactions. Clients value his attitude, with one describing him as 'technical, available and pleasant.' »
Chambers Europe 2021

« Draws impressive praise from sources, who value his skills in tax litigation. One client reports: "He analyses cases in real depth and has an exceptional ability to find solutions. It's very easy and pleasant to work with him as he is an excellent listener and has a real sense of service." »
Chambers Europe 2020

« Advises on a variety of matters, including tax litigation, real estate investments, M&A transactions and capital markets operations. Frequently works on international matters. Clients come from different industry sectors such as financial services, real estate and retail. Draws on expertise from across the firm to provide a holistic service to clients. Clients describe the lawyers as 'responsive, committed and providing high-level strategic tax advice on sophisticated transactions or litigation cases.' Another highlights their 'competence, pragmatism and negotiation ability.' Head of department Olivier Dauchez  advises clients on a wide range of tax matters including litigation and tax structuring of M&A and capital markets operations. One client comments: 'He is solution-oriented and acts as a true business partner.' »
Chambers Europe 2019

« Gide Loyrette Nouel has ‘an extremely responsive, innovative and committed’ team, which ‘provides high-level advice on sophisticated litigation and complex transactions’. The 16-lawyer practice can also rely on 'a good international network and is well connected with industry bodies, as well as governmental and regulatory agencies’. The team notably has ‘deep knowledge of the real estate sector’ and regularly advises on high-profile transactions in that area. It recently assisted Amundi Immobilier and Primonial with the set up of a joint venture for the off-plan acquisition of the Tour Hekla project. The team is also very strong in the banking and financial sector and recently assisted CNP Assurances with the issuance of €500m-worth of Tier 1 notes. Olivier Dauchez ‘demonstrates impressive capabilities to anticipate tax and litigation developments relying upon his broad experience’ and ‘provides strategic assistance with complex situations’. »
Legal 500 EMEA 2019

Best Lawyers in France (2021) : Avocat de l'année en Trust & Estates ;  référencé comme l'un des meilleurs avocats en droit fiscal

International Who's Who Legal Corporate Tax Lawyers (2020) : référencé