Saisie-contrefaçon attorney: patent evidence in France
The saisie-contrefaçon is the central evidentiary instrument of French patent litigation. It is prepared before the application, decided on the day of execution and defended afterwards. Dhenne Avocats acts at all three stages, for applicants and respondents alike, before the Paris Judicial Court and before the Unified Patent Court.
How we act
- Drafting the ex parte application and defining the scope of the mission entrusted to the commissaire de justice.
- Appointing and briefing the independent expert who accompanies the operation.
- Assistance on the day of execution and handling of incidents.
- Sequestration and the debate on the seized party's trade secrets .
- The action on the merits within the prescribed time limit, failing which the seizure is void.
- For respondents, withdrawal of the order, challenges to the operations and release of the sequestration.
Evidence and information obtained
The judge may authorise a detailed description, with or without the taking of samples, or the physical seizure of the products and processes alleged to infringe. The remit may extend to technical and accounting documents: drawings, laboratory notebooks, invoices, purchase orders, lists of customers and suppliers. That is often where the extent of the loss is decided, even more than the existence of the infringement.
Obtaining the order
The measure is ordered on an ex parte application, without the opponent being informed. The applicant must establish its standing and produce its title. The drafting of the application governs everything that follows: it fixes the scope of the remit, the premises concerned, the categories of documents sought and the powers of the bailiff (commissaire de justice). A remit that is too broad invites withdrawal of the order. One that is too narrow leaves the evidence behind.
Execution
The operations are conducted by a bailiff, assisted where appropriate by an expert independent of the applicant, and sometimes by the police. The applicant’s counsel does not attend. The preparation of the bailiff and the expert (what they must look for, how to describe it, what they must not do) determines the value of what will be reported.
Sequestration and trade secrets
The party seized may ask that the items taken be placed under sequestration pending a decision on their disclosure. The judge then weighs the applicant’s right to evidence against the protection of the trade secrets of the party seized. This phase, often neglected, decides in practice what the claimant will actually be able to produce at trial.
The deadline to sue on the merits
The seizure must be followed by an action on the merits within a short period, failing which the party seized may have it annulled, without having to give reasons, and the evidence gathered is then lost. That period runs from the operations. It is neither extended nor negotiated: it is calculated on the day of the seizure and kept.
- Before the seizureEx parte application to the President of the CourtOrder made without adversarial argument. The applicant gives a candid account of its title, the facts and the remit sought.Art. L. 615-5 IPC
- Day DExecution of the operationsBailiff (commissaire de justice), assisted where appropriate by an independent expert: description, samples or physical seizure. The party seized may ask for sensitive documents to be placed under sequestration.Art. R. 615-4 IPC, Art. R. 153-1 Commercial Code
- D + 1 month at mostApplication to the judge on the sequestrationUnless an application to vary or withdraw the order is made within one month of its service, the provisional sequestration is lifted and the documents are handed to the applicant.Art. R. 153-1 Commercial Code, Art. 497 CPC
- D + 20 working days or 31 calendar daysAction on the merits by the seizing partyThe longer period applies. Failing that, the seizure, including the description, is set aside at the request of the party seized.Art. L. 615-5 and R. 615-6 IPC
- ThenArgument on the sequestered documentsDocument-by-document sorting between what is covered by trade secrets and what the dispute requires: non-confidential versions, restricted access.Art. L. 153-1 and R. 153-2 et seq. Commercial Code
- At any timeWithdrawal of the order and nullityThe party seized may ask the judge who made the order to withdraw it and challenge the operations before the trial court (exceeding the remit, want of candour, expert lacking independence).Art. 496 and 497 CPC
- On the meritsUse of the evidenceThe findings and the documents disclosed serve to establish infringement and to quantify the loss.Art. L. 615-7 IPC
Sources: Intellectual Property Code (Art. L. 615-5, L. 615-7, R. 615-4, R. 615-6), Commercial Code (Art. L. 153-1, R. 153-1 et seq.), Code of Civil Procedure (Art. 496 and 497). Indicative outline drawn up on 16 October 2026.
For applicants: a seizure that withstands challenge
The saisie-contrefaçon is authorised on an ex parte application, in the absence of the future party seized. That departure from the adversarial principle has a counterpart: the applicant owes the court a fair and complete account of the facts, including those unfavourable to it. Pending opposition proceedings, a foreign decision or a limitation of the claims left unmentioned are all grounds for withdrawal of the order.
The second point of weakness is the scope of the remit. Too broad, it exposes the measure to a complaint of disproportion. Too narrow, it leaves the evidence behind. We draft the remit from the claim relied upon and the product concerned, not from a standard formula.
For respondents: challenging a seizure
The party seized is not without remedies. Withdrawal of the order may be sought from the judge who made it, in particular for want of candour, insufficient presentation of the title or disproportion of the remit. The operations may be declared void for exceeding the remit or irregular execution. Failure to bring an action on the merits within the period laid down in Article R. 615-6 of the Intellectual Property Code results in the seizure being void.
Sequestration is the other battleground. Documents covered by trade secrets are released to the seizing party only after adversarial argument, within the framework of Articles L. 153-1 et seq. of the Commercial Code. That argument is prepared: the task is to identify, document by document, what is covered by secrecy and what is necessary to resolve the dispute.
A seizure is not a foregone conclusion for the party that obtains it. The party seized has the application for withdrawal, the application for release, the challenge to the report and the protection of its trade secrets. The most frequent irregularities concern exceeding the remit, an insufficient application or a lack of independence of the expert.
French saisie or a measure before the UPC
Since the unitary system came into force, the same act of infringement may give rise to a saisie-contrefaçon under French law or to a measure to preserve evidence underArticle 60 of the Agreement on a Unified Patent Court. The two routes differ in territorial reach, in the regime governing disclosure of documents and in their consequences for the rest of the dispute.
The choice is made case by case, according to the title, the location of the evidence, the existence of an opt-out and the overall strategy. We make that choice before the application, never after.
A few matters that illustrate our practice
Biotechnology: evidence and protection strategy
Strategic advice to a biotechnology company on the protection of manufacturing processes for biological medicinal products. Preparation of an evidence strategy, analysis of the saisie-contrefaçon options and review of the routes open before the French courts and the Unified Patent Court.
Biological medicines: challenging saisie-contrefaçon orders
Involvement in challenging saisie-contrefaçon measures in the biologics sector. Analysis of the conditions for obtaining the orders, the proportionality of the measures and the extent of the documents seized, in their articulation with the litigation on the merits.
Analyses and publications to go further
Frequently asked questions
What should you bring to prepare a saisie-contrefaçon?
The patent, a first infringement analysis, the products or processes targeted and the places where the evidence is located. The mission must remain justified and proportionate.
Can a company that has been seized challenge the measure?
It may contest the order, its execution and the communication of the documents through the applicable routes. Trade secrets and the timetable of the litigation on the merits are checked immediately.
Are the French seizure and the UPC evidentiary measures interchangeable?
They pursue similar aims under different regimes. The forum, the scope of the evidence and its communication govern the choice.
Discuss your matter
A saisie-contrefaçon can be prepared in a matter of days once the material is in place, and the timetable is often driven by a trade fair, a market launch or a corporate transaction. Write to us : we will tell you quickly whether the measure is appropriate and in what form.