• Recognition of neighbouring rights in favour of record producers and performers.

In the early 1980s, more than a decade before neighbouring rights were formally recognized by statute in Belgium, Thierry succeeded, acting on behalf of both record producers and performers, in securing unanimous case law that rapidly eradicated the then rampant practices of record piracy and bootlegging by characterizing them as acts of unfair commercial practices.

• Recognition of the designation of origin 'Havana' for tobacco and cigars.

Whilst in the late 1980s this designation of origin was not legally recognised in most Western European countries and was apparently becoming a generic term, Thierry, on behalf of the Cuban state-owned company ‘Cubatabaco’, obtained two authoritative precedents before the Courts of Appeal of Brussels and Liège which confirmed the validity of this designation of origin, whereupon Swedish Match, under whose authority many cigar manufacturers, particularly those based in the Netherlands, used terms such as 'Wilde Havanas' had to cease the use thereof.

• The concept of ‘likelihood of association’ in trade mark disputes

Thierry appeared before the Benelux Court of Justice on behalf of Julien in the Julien v Verschuere landmark case, in which the concept of the ‘likelihood of association’ in trade mark disputes was recognized for the first time within the EU by a judgment of 20 May 1983.

• Relevant factors for determining the scope of protection of trade marks

On behalf of Kortman Redipro, the former owner of the Biotex trade mark, Thierry appeared in the case bearing the same name before the Benelux Court of Justice, which, in its judgment of 29 June 1987, at the request of the Court of Appeal of Ghent, identified a number of factual circumstances which are not such as to reduce the scope of protection of the trade mark, in line with the current case law of the EU Court of Justice.

• Burden of proof and exhaustion

Also before the Benelux Court of Justice, Thierry secured the Kipling judgment of 6 December 1999, in which it was held for the first time within the EU that the burden of proof regarding the exhaustion of a trade mark invoked by a third-party user rests, in principle, entirely with that party and must relate to each individual item of the trade marked products in question, a position which the EU Court of Justice confirmed in its judgment of 20 November 2001 in Case C-414/99.

• Distinctive character of trade marks

Before the EU Court of Justice, Thierry successfully defended the validity of the word mark ‘Baby-Dry’ for nappies, which the Office had refused to register on the grounds that the sign was allegedly purely descriptive. This landmark judgment was delivered on 20 September 2001 in Case C383/99. It was the first judgment rendered by the Court, sitting as a court of cassation, in proceedings relating to an application for registration of a EU trade mark.

• Validity of position marks

Equally high-profile was Thierry’s long-standing and successful battle to defend the ab initio validity of Louboutin’s red sole trade mark for high-heeled shoes. The decisive judgment was delivered by the Grand Chamber of the EU Court of Justice on 12 June 2018.

• The use of a trade mark by an online marketplace

Thierry’s sustained efforts, notably on behalf of Louboutin, to have Amazon recognized as the user of all trade marks under which products are offered on Amazon’s platforms led to the landmark judgment of the Grand Chamber of the Court of Justice of 22 December 2020, which upheld his position. All such uses were indeed attributable to Amazon.

• Reprography levies

Thierry successfully advocated to have the EU Court of Justice rule that the Belgian system of reprography levies is contrary to EU law, first through its judgment in HP v Reprobel of 12 November 2015 and subsequently by its judgment in Copaco v Reprobel of 14 November 2024, with the result that the Belgian State is obliged to reimburse all fees paid over a period of almost 20 years.