Biography

Guillaume began his legal career in tax in Paris before relocating to Melbourne, where he has built over ten years’ experience at leading Australian law firms.

He has extensive experience managing complex and disputed engagements with the ATO, State Revenue Offices and other regulators, including AusIndustry for R&D claims. His work spans the full dispute lifecycle, from voluntary disclosures and early investigations to audits, objections, internal reviews, and tribunal and court proceedings. He advises and represents taxpayers in tax‑related disputes, including professional liability matters, director liability, and tax debt recovery proceedings involving the Commissioner’s statutory powers.

Guillaume has deep technical expertise in GST, providing both disputes and front‑end advisory services. His experience includes advising a State government on the GST treatment of forestry supply chains, advising a large institutional organisation on the GST treatment of green products and related contractual settlements, and representing a support services industry leader in a large‑scale GST audit.

Dual‑qualified in France and Australia, Guillaume brings a strong cross‑border perspective to tax matters involving French and Australian interdependencies, including interactions between the two tax regimes and regulators.

Guillaume's experience