An Expert Witness Guide to Justice Systems: France

By Noah Bolmer 

Legal systems vary widely across the world, but one of the most fundamental distinctions is between civil and common law traditions. Civil law, found in countries like France, Germany, and Japan, is based on codified statutes and emphasizes judicial control over proceedings. Common law systems, such as those in the United States and the United Kingdom, rely more heavily on precedent and adversarial courtroom dynamics, although there is still a codified foundation. These structural differences shape how expert witnesses are used, evaluated, and perceived. 

France, with its deeply rooted civil law framework, offers a particularly clear example of how expert testimony functions in a non-adversarial setting. As in the US, the role of the expert is not to advocate for a party but to assist in understanding technical matters, but in France, it is through a formal, court-directed process. 

A Judicial Model 

France’s justice system is built around the principle of judicial investigation. In contrast to the adversarial model used in the United States, French judges play an active role in gathering and evaluating evidence. This is true in both civil and criminal cases, where the judge—not the attorneys—controls the pace and scope of the proceedings. 

The system is divided into several branches: 

• Civil courts handle disputes between individuals or organizations. 

• Criminal courts address violations of the penal code. 

• Administrative courts deal with conflicts involving public authorities. 

Judges in France are career professionals trained at specialized institutions and are expected to maintain strict neutrality. Their role is not to referee between opposing sides, but to uncover the truth through structured inquiry. This judicial philosophy naturally extends to the use of expert witnesses, who are seen as technical collaborators rather than partisan advocates. 

Attorneys, known as avocats, still play an important role in presenting legal arguments, advising clients, and responding to evidence including expert reports. However, their influence over the fact-finding process is more limited than in common law systems. They do not control the presentation of evidence or the examination of witnesses in the same way. Instead, they work within the framework established by the judge, contributing legal reasoning and interpretation rather than driving the narrative. This balance between judicial authority and legal advocacy reflects the broader structure of the French system. 

France’s use of expert witnesses is a deeply embedded feature of its legal tradition, dating back centuries. One of the earliest formal recognitions of expert involvement in judicial proceedings came with the Ordinance of 1667, issued under King Louis XIV. This sweeping reform of civil procedure laid the groundwork for many aspects of the French legal system that persist today, including the structured use of experts. 

The ordinance explicitly authorized judges to appoint experts to assist in resolving technical questions beyond the court’s knowledge. These experts were considered auxiliaries of justice, tasked with helping the judge reach an informed decision. This early codification established a precedent for judicial reliance on neutral, court-appointed experts—a principle that remains central to French procedure. 

In contrast, the United States did not formalize the role of expert witnesses at a federal level until much later. While experts appeared in American courts during the 19th century, their use was largely shaped by evolving case law and adversarial practice rather than centralized codification. The Federal Rules of Evidence, which now govern expert testimony in US federal courts, were only adopted in 1975, more than three centuries after France’s ordinance. This historical divergence underscores a key philosophical difference: France’s legal system has long treated expertise as a judicial tool, integrated into the court’s own investigative function. In the US, expertise developed as a strategic asset wielded by litigants. Understanding this legacy helps explain why French courts continue to favor court-appointed experts. 

Court-Appointed Experts 

Expert witnesses in France are typically appointed by the court rather than hired by the parties. These experts (éxperts judiciaires) must be registered with the court and meet rigorous qualifications including demonstrating expertise in a specific field and being listed in an official directory. This system ensures that experts are not only qualified but also recognized as neutral contributors to the judicial process. 

Once appointed, the expert’s role is to investigate and report on technical questions posed by the judge. These experts conduct their investigations independently, often visiting sites, reviewing documents, and interviewing relevant parties. Their findings are delivered in detailed reports, which often carry significant weight in the final judgment. These reports are expected to be thorough, methodical, and free from advocacy.  

While most French legal proceedings are judge-led, jury trials do exist—but only in serious criminal cases. The jury is composed of citizen jurors (typically six, and then nine on appeal) who deliberate alongside three professional judges. This mixed panel votes together on both guilt and sentencing, with judges guiding the process and ensuring legal standards are upheld. Unlike in common law systems, where juries operate independently, French jurors are part of a collaborative decision-making body. 

In these cases, expert witnesses may still be appointed by the court, particularly in matters involving forensic science, psychiatry, ballistics, or medical evidence. Their reports are submitted to the court and shared with both the judges and jurors. While experts may be called to testify, their role remains primarily explanatory rather than adversarial. Judges often lead the questioning, and attorneys may pose additional questions, but cross-examination is limited. The presence of a jury does not fundamentally alter the expert’s function; they remain a neutral resource, helping the entire panel understand complex technical issues. This reinforces the French emphasis on impartial expertise, even in the context of criminal trials involving public participation. 

Party-Appointed Experts: A Supporting Role 

While parties in France can submit their own expert opinions, these are generally viewed with skepticism. The court-appointed expert’s report is considered the authoritative source, and party experts are seen as potentially biased. Their role is supplementary; used to challenge or contextualize the court’s findings. 

For instance, if a party disagrees with the conclusions of the court-appointed expert, they may commission a counter-report (equivalent to a rebuttal report in the US). However, this report will not carry the same weight unless it raises significant doubt or identifies clear errors. Judges may consider it, but they are not obligated to give it equal standing. This dynamic contrasts starkly with the American model, where dueling experts are a staple of litigation.  

Limited Role of Cross-Examination 

One of the most striking differences from the American system is the limited role of cross-examination. In the US, expert witnesses are often central figures in trial strategy, subject to intense scrutiny and cross-examination aimed at undermining their credibility. In France, the process is far more restrained. 

If clarification is needed, judges may summon the expert for a hearing. These sessions are typically informal and focused on understanding the report, not challenging the expert’s integrity. Lawyers may be present, but the tone remains investigative rather than adversarial. The goal is not to discredit the expert but to ensure the judge fully understands the technical aspects of the case. 

Expert Missions and Judicial Oversight 

When a judge appoints an expert, they define the scope of the investigation, known as the mission. This directive outlines the questions to be answered and the methods to be used. The expert must remain within these bounds and report back to the court. Throughout the process, the judge retains oversight, ensuring that the expert’s work aligns with the legal and procedural framework. The mission not only guides the expert’s work but also sets expectations for the parties—everyone involved knows what the expert is investigating and what the final report will address. This transparency helps maintain trust in the process and reinforces the expert’s role as a neutral fact finder. 

Experts are also expected to communicate with the parties during their investigation, often through written correspondence or scheduled meetings. However, they must maintain impartiality and avoid any appearance of favoritism. Their final report is submitted to the court and shared with all parties, who may respond or request clarification. 

Payment 

In France, the remuneration of court-appointed expert witnesses is governed by judicial oversight and codified procedures. Compensation is determined based on the complexity of the case, time spent, and the nature of the expertise provided. The initial payment—called a provision—is ordered by the court and advanced by the party (or parties; both sides may make a joint request) requesting the expert. After the expert submits their final report, the court assesses the total fee and authorizes final payment. These fees are subject to approval by the judge and are reimbursed as part of litigation costs under Article 695 of the French Code of Civil Procedure. As the provision is treated as an advance it may be replenished during the course of the engagement. 

Key Differences from the US System 

While both France and the United States require expert witnesses to be impartial, the procedural context in which they operate differs significantly. In the US, experts are typically retained by one of the parties, and although they are legally bound to provide neutral, objective opinions, their testimony is often presented in a way that supports the retaining party’s case. This adversarial setting means their impartiality is frequently challenged, and their credibility tested through cross-examination. The court relies on the opposing side to expose any weaknesses or bias in the expert’s analysis. 

In France, experts are almost always appointed by the court and serve as auxiliaries of justice. Their role is generally to assist the judge directly; not the parties. Because they are selected from an official registry and operate under judicial oversight, their neutrality is structurally reinforced. Cross-examination is rare, and party-appointed experts, while permitted, are viewed with caution and generally carry less weight. Thus, while the ethical expectations of neutrality are shared across both systems, the procedural safeguards and perceptions surrounding expert testimony differ. 

Conclusion 

Whether or not one ever works within the French system, understanding its structure offers valuable insight into the diversity of legal thought and practice. It’s a reminder that the role of the expert witness is not fixed—it evolves with the legal context, shaped by the values and traditions of the system in which it operates. 

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