Court-appointed expert witness and IP: the strategic asset for asset security
In an economic landscape where corporate value is increasingly derived from intangible assets, intellectual property (IP) litigation is becoming significantly more complex. The increasing judicialization of business, coupled with the technical intricacies of emerging digital challenges (Web3, AI, Data), imposes a requirement for absolute rigor upon legal practitioners. For international lawyers, General Counsels, and decision-makers, relying on standard technical support is no longer sufficient; it has become imperative to collaborate with professionals whose competence is recognized and validated by the highest jurisdictions.
It is in this context that the dual status of Court-Appointed Expert to the Cour de cassation (French Supreme Court – Specialization: Trademarks) and Expert to the Paris Court of Appeal (Specialization: Trademarks, Designs & Models) assumes its full strategic dimension. Beyond the honorific title, it represents a probative methodology and an anticipatory vision of judicial risk that are placed at the service of corporate strategy. This qualification offers reinforced legal certainty, which is essential for preserving the professional liability of legal counsel and ensuring the enforceability of rights holders’ assets.
The status of court-appointed expert: a guarantee of technical excellence and ethics
Inclusion on the lists of judicial experts is not a mere administrative formality. It is the culmination of a drastic selection process, validating indisputable technical competence and absolute moral probity.
Being a Court-Appointed Expert to the Cour de cassation constitutes the highest level of recognition for a legal technician in France. This implies that the highest court in the French judicial order recognizes the expert as an authority in their specialization. Similarly, accreditation by the Paris Court of Appeal, the central jurisdiction handling the vast majority of IP litigation in France, attests to a proven practice in complex cases.
For the lawyer or the final client, collaborating with a Court-Appointed Expert offers three major guarantees, indispensable to the solidity of a file:
- Independence: The expert is bound to total objectivity, a pledge of credibility when establishing reports or audits.
- Technical Competence: Mastery of the most specific aspects of the matter (distinctiveness, likelihood of confusion, revocation, materiality of infringement).
- Ethics: Strict adherence to the guiding principles of the trial, notably the adversarial principle (due process), which permeates their entire practice, even in advisory roles.
You may verify these official registrations via the justice directories:
- Consult the official list of experts to the Paris Court of Appeal (2026)
- Consult the official list of experts to the Cour de cassation (2025)
- Consult the national directory of the National Council of Companies of Justice Experts (CNCEJ)
The added value of the judicial expert in the lifecycle of IP rights
A common misconception is that the Court-Appointed Expert only intervenes once litigation has arisen. On the contrary, it is precisely upstream, in the daily management of portfolios, that the judicial expert’s mindset provides superior legal certainty. Each act is performed with the perspective of its future enforceability before a tribunal.
Audit and availability searches: the judge’s eye before the trial
A standard availability search lists potential obstacles. A search conducted with “the eye of the Court-Appointed Expert” qualifies the risk with the perspective of the magistrate. The expert, accustomed to enlightening tribunals, understands how trial judges appreciate in concreto the similarity of signs or goods and services.
When analyzing your trademark availability searches, we do not merely apply theoretical criteria. We evaluate the probability that a judge would retain a likelihood of confusion, integrating the most recent jurisprudential trends. This allows for the elimination of false positives (theoretical risks that are judicially weak) and the identification of genuine litigation risks, thus protecting the company against future nullity actions.
Filings and procedures: procedural rigor at the service of protection
The solidity of an industrial property title is determined at the moment of its filing. A poorly drafted specification or imprecise classification constitutes a breach into which the opposing party will step during a nullity or revocation action.
The practice of pathological litigation teaches us a contrario how to draft robust wordings. We anticipate arguments of non-use or lack of distinctiveness. This preventive approach is at the heart of our trademark law practice, where each class is weighed to withstand the “fire” of judicial proceedings, guaranteeing maximum enforceability of the title. This is essentially legal engineering designed to preclude future vulnerability.
Management and valuation: credibility in audits (M&A)
In the context of Mergers & Acquisitions (M&A) or fundraising, the valuation of IP assets is critical. The intervention of an Expert appointed to the Cour de cassation to audit a portfolio provides a major “trust signal” to investors and auditors.
The financial valuation of trademarks requires rigorous methodology (relief from royalty method, excess earnings method, etc.) which the judicial expert masters perfectly for regular presentation before the courts. This rigor secures the valuation and strategy and minimizes the risks of liability warranties, thereby protecting the professional liability of the business lawyers managing the transaction.
Surveillance and defense: qualifying infringement with precision
Online brand enforcement often generates significant “noise.” Distinguishing between a minor infringement and a substantiated counterfeiting case requiring immediate action is crucial for cost control and defense strategy.
The Court-Appointed Expert possesses the necessary acuity to detect the constitutive elements of infringement (identical reproduction, imitation, risk of association) and to compile a body of probative evidence. This precise qualification allows for advising on the most adapted gradual response, from the cease-and-desist letter to the seizure (saisie-contrefaçon), avoiding reckless threats that could lead to liability for disparagement.
The synergy between lawyers and IP attorneys in complex litigation
The success of intellectual property litigation often rests on the alliance between the procedural strategy of the lawyer and the technical analysis of the Trademark Attorney (CPI). When a specialized lawyer collaborates with a CPI holding the status of Court-Appointed Expert, they significantly reinforce the probative value of their file.
This technical collaboration materializes at several levels:
- Expert Consultation (Party-Appointed Expertise): Even before the introduction of proceedings, we can draft an independent technical consultation. Although produced at the request of a party, the signature of an Expert appointed to the Cour de cassation confers major technical weight upon the document. This report serves to objectify technical facts and provides the lawyer with robust arguments for their pleadings, which can be pivotal in IP litigation advice.
- Assistance during Saisie-Contrefaçon (Seizure): The preparation of the motion and assistance to the Bailiff during operations require surgical precision to avoid the nullity of the official report. Judicial expertise ensures scrupulous respect for the limits of the court order and the accurate description of material facts.
- Validity Analysis and Counterclaims: In a defense strategy, we assist the lawyer in identifying technical flaws in the opposing party’s patent or trademark (prior art, lack of novelty, descriptiveness) to construct a solid counterclaim for nullity.
This synergy allows for the delivery of a “turnkey” file to the judge, where law and technique articulate perfectly, maximizing the chances of success.
FAQ: The judicial expertise in practice
What is the difference between a Party-Appointed Expert and a Court-Appointed Expert?
The Court-Appointed expert is designated by the judge to enlighten the tribunal on a technical question with total impartiality. The Party-Appointed expert is retained by one of the parties. However, when the party expert also holds accreditation from the Cour de cassation or Court of Appeal, their private consultation benefits from superior moral and technical authority. They remain bound by their ethics and duty of rigor, which confers greater probative force to their analysis than a simple technical note.
How does judicial expertise secure a trademark financial valuation in an M&A context?
The financial valuation of intangible assets is often contested by tax authorities or during shareholder disputes. The judicial expert applies standardized methodologies recognized by the courts. Their valuation report is argued, documented, and justified point by point. In the event of an audit or post-acquisition litigation, this report constitutes a master piece of evidence to justify the transfer price, thus protecting executives and their legal counsel.
Can we retain a Court-Appointed Expert for a private consultation before litigation starts?
Yes, and it is highly recommended. Retaining a Court-Appointed Expert for a pre-litigation consultation allows for an objective assessment of the chances of success of an action (analysis of the materiality of infringement, validity of the title). This enables the lawyer and client to define the best strategy: settle, attack, or withdraw. It is an indispensable risk management tool to avoid long, costly, and uncertain proceedings.
What is the role of the expert during a saisie-contrefaçon?
During a seizure, the Bailiff describes what they see, but they do not always possess the technical competence to identify specific elements of infringement, particularly in complex fields (software, designs). The expert assisting the Bailiff guides them to ensure that the seized evidence corresponds exactly to the judge’s order, thus avoiding out-of-scope seizures that could lead to the nullity of the report.
Why trust Dreyfus Law Firm
Dreyfus Law Firm is not merely a firm of Trademark Attorneys; it is a reference in Intellectual Property and Digital Law.
Founded by Nathalie Dreyfus, Expert to the Cour de cassation and Expert to the Paris Court of Appeal, the firm combines the agility of a dedicated team with the power of a global network. Our transversal approach allows us to accompany lawyers and legal departments across the entire value chain: from filing strategy to aggressive defense of rights on the Internet (Domain names, UDRP, Phishing) and in the physical world.
Choosing Dreyfus means choosing the security of technical expertise recognized by the highest French jurisdictions to protect your most valuable assets and secure your litigation strategies.
Are you a lawyer or General Counsel looking to secure the technical aspect of a complex file?
Contact us for a confidential analysis of your issues.
Dreyfus & Associés is a partner of a global network of lawyers specializing in Intellectual Property.



















