Mikaël has been a member of the Brussels Bar since 2004. He joined JANSON as a partner on 1 July 2025.

He previously worked at Hirsch & Vanhaelst, Afschrift and Philippe & Partners, where he acquired extensive experience in corporate and personal taxation, including VAT and corporate reorganisation transactions.

His practice encompasses tax, administrative and judicial advice and litigation. He is also involved in obtaining advance rulings from the Advance Rulings Department.

Mikaël works in both French and English.

Mikaël holds various academic positions, enabling him to enrich his professional practice with rigorous theoretical foundations and to share theoretical knowledge informed by substantial practical experience.

Accordingly, he is:

• Associate Professor, member of the Centre for Private Law of the Université Libre de Bruxelles (Tax Law Unit)

• Internship supervisor at the Université Libre de Bruxelles

• Lecturer in the Executive Master in Tax Management at the Solvay Brussels School

• Assistant responsible for Exercises in Tax Law at the Université Libre de Bruxelles, Faculty of Law and Criminology.

• Securing multiple advance rulings in respect of various transactions (emigration of companies, share contributions to holding companies, VAT rates applicable to the sale of buildings, application of the definitively taxed income regime, debt write-offs, etc.)

• Representing taxpayers, both individuals and legal entities, during tax audits, including audits conducted by the Special Tax Inspectorate

• Advising companies on the sale of their assets and on the fiscal optimisation of their liquidation operations

• Advising individuals and legal entities on the sale of shares in companies, including real estate companies

• Advising real estate developers on the VAT rates applicable to certain real estate works (6% or 21%) and to the sale of residential properties (6% or 21%)

• Obtaining favourable decisions from tax authorities and courts in a range of matters (copyright, tax abuse, preservation of loss deductibility following a 10% increase, procedural breaches during home searches, VAT rates applicable to major renovation works, etc.)

Education :

Diploma of Advanced Studies in Tax Law from the Université Libre de Bruxelles (2008, magna cum laude, promotion major)

Specialised Diploma in Corporate Law from Ghent University (2004)

Degree in Law from the Université Libre de Bruxelles (2003)

Bar : Brussels

Mikaël is the author of numerous contributions, including:

• M. GOSSIAUX, « Les pouvoirs d’investigation en matière de TVA », in François Stévenart Meeûs (dir.), Les pouvoirs d’investigation du fisc et les délais d’imposition, Louvain‑la‑Neuve/Bruxelles, Anthemis, 17 décembre 2024, pp. 227-241

• M. GOSSIAUX et S. COPPOLA, « Responsabilité personnelle des dirigeants et de leurs conseillers », in François Stévenart Meeûs (dir.), Les pouvoirs d’investigation du fisc et les délais d’imposition, LouvainlaNeuve/Bruxelle , Anthemis, 17 décembre 2024, pp. 403-433

• M. GOSSIAUX et M. BONNEURE, Aspects particuliers de la procédure fiscale et pénale en matière de fraude fiscale, RPSTRV 2023, liv. 7, pp. 527-537

• M. GOSSIAUX, « La réception du trust en droit fiscal belge », R.P.P., 2020, pp. 316-322

• M. GOSSIAUX et A. WILLEMS, Prouver la réalité des prestations rémunérées : un point d’actualité sur la théorie de la rémunération, R.G.F.C.P. 2020, liv.4, pp. 13-21

• M. GOSSIAUX, « La Taxe Caïman ou la taxation par transparence des constructions juridiques », R.G.C.F., 2015, pp. 303-319

• M. GOSSIAUX et S. VANHAELST, « Les implications fiscales d’une réorganisation judiciaire au regard de la loi sur la continuité des entreprises », Actualité de la continuité, continuité de l’actualité. Etats généraux de la continuité, Bruxelles, Larcier, 2012, pp. 547-570

• M. GOSSIAUX, « La portée de l’article 313 CIR 92 et son influence sur le boni de liquidation de l’année 2002 », C.F.P., 2009, liv. 1, pp. 28-34