Digital forensic expertise
This page sets out the digital forensic practice: the frameworks under which engagements take place, the working method, the deliverables to expect and the points requiring particular care when working on data, devices and systems.
A court-appointed digital forensic expert, Yann Sanchez belongs to several French associations of court-appointed experts: the Compagnie des experts de justice en criminalistique (CEJC, the forensic science experts' association; admitted as an active member on 1st September 2026), the Compagnie des Experts de Justice de Lyon (the Lyon association of court-appointed experts) and the Compagnie Nationale des Experts de Justice en Informatique et Techniques Associées (CNEJITA, the French national association of court-appointed IT experts; admitted on 2 September 2026). He is also a member of AFSIN, the French-speaking association of digital investigation specialists.
Professional affiliations
Membership of these professional associations is personal and separate from the company YSAX; it constitutes neither a certification nor an accreditation.
Availability
Yann Sanchez is listed with the Lyon Court of Appeal (Cour d'appel de Lyon) as an expert in the digital field. In France, courts appoint their experts from the registers held by each court of appeal, and being entered on such a register follows a formal application and vetting procedure. He can therefore consider requests for court-appointed digital forensic work in Lyon and the surrounding areas whenever the terms of the engagement allow.
The listing is attached to one court of appeal, but it does not confine the work to that area: a court anywhere in France may appoint an expert listed elsewhere. Cases located in other parts of the country can therefore be scoped on a quotation basis, with remote preparation or travel to site where physical presence genuinely adds value to the case.
Common situations
An employee leaving, the suspected extraction of customer files, document transfers, disputed use of a business application or unusual access to data.
Confidential documents, customer databases, strategic files, exports, access logs or traces that help establish what actually circulated.
A web page, a post, an account, a mailbox, a profile, a collaborative workspace or any content that may be altered, deleted or disputed.
Sign-ins, forwarding rules, settings, conversations, attachments, administration traces or anything useful in building a timeline.
History, exports, an accessible database, application logs or internal data needed to explain a commercial or operational dispute.
Computers, phones, removable media, backups or logs to be cross-referenced in order to establish a consistent timeline.
Method
Identify the context, the legal framework, the urgency, the people concerned and what the analysis is meant to help establish or rule out.
Map out the devices and media, accounts, access rights, data volumes, practical constraints and known limitations before any collection or on-site work.
Collect, preserve or analyse the relevant material, documenting the actions taken, the technical choices made, any incidents and the limitations encountered.
Produce usable findings, structured for technical and non-technical readers alike, with care in distinguishing what is established, what is probable and what is uncertain.
What you receive
A clear view of the scope, the objectives, the devices and media and the constraints before committing to heavier work.
Copies, exports, captures, logs or technical items collected in line with the terms of the engagement and documented so that they remain readable.
Dates, access events, files, events, accounts and actions brought together to help understand what most likely happened.
Structured reporting that distinguishes findings, hypotheses, limitations and the points where further material is needed.
Article 145 CPC
Skills applied
Computers, phones, removable media, backups, GPS units, cameras and application environments.
See the devices analysedLogs, metadata, files, system artefacts, conversations, events and time correlations.
Structured reports, technical appendices, summaries a non-specialist can follow, and explicit statements of the limitations of the analysis.
Frequently asked questions
Yes. Being listed with the Lyon Court of Appeal and based in Lyon makes local engagements straightforward, while still allowing requests from anywhere in France to be considered, depending on the framework, the deadlines and whether travelling is genuinely worthwhile.
Requests may arise from a court appointment, a private (non-court-appointed) engagement, technical assistance to a judicial officer, an Article 145 measure or a pre-litigation matter that calls for digital analysis.
A first conversation clarifies the legal framework, the devices and media concerned, the deadlines, the people who will be present, the access available and the constraints on collection or analysis.
Not always. Depending on the case, part of the scoping, the analysis or the reporting can be done remotely; travelling to site is preferred when it adds concrete value to the collection or to the understanding of the facts.
Any IT specialist can provide a technical analysis. A court-appointed digital forensic expert is something more specific under French law: the title corresponds to an official listing on the register of experts held by a court of appeal (cour d'appel), granted after a formal application and vetting procedure and reviewed periodically. French courts appoint their experts from those lists, and the expert then works under a court order as an independent officer assisting the court, not as a party's adviser. In practice this means heightened attention to evidence, to the traceability of every operation performed, to the adversarial principle (both sides heard) and to reporting that the court, the parties and their lawyers can actually use.
Anonymised references
Technical assistance during an operation aimed at identifying specific customer files, in a sensitive context requiring procedural rigour and adaptation to the environment encountered.
Extensive analysis in a long-running case, covering location data, photographs, encrypted messages, text messages and other relevant digital material, across a large number of devices.
Work with the justice system
Engagements and collaborations in judicial and investigative settings, with a constant requirement for technical rigour, traceability and adaptation to the context.
Courts
Investigation services
Technical support in civil litigation, in particular for digital investigation operations and the search for usable technical evidence.
Judicial officers' firms (études de commissaires de justice)
Tools