On Thursday 2 July 2026, a company in Grasse that imports essential oils receives a registered letter from the Marseille regional investigation unit. Three pages, no more. The administration states that the authorities of the exporting country, questioned in the course of a post-clearance verification, have not confirmed the preferential origin declared on forty-one imports, and that it intends to claim 134,000 euros in duties. The letter refers to Article 22(6) of the Union Customs Code, allows thirty days to submit observations and mentions the possibility of consulting the verification report.
The finance director replies the following Wednesday with a ten-line email: the supplier is reliable, the origin declarations were in order, the company disputes the claim. On 13 July, the administration takes its decision. Eleven days later. Nothing irregular about it: the implementing regulation allows the authorities to decide as soon as the person has expressed a point of view, unless that person has indicated an intention to supplement it. The case, which turned on the adversarial exchange, went to litigation without the company ever having read the report.
This page does not revisit the conduct of the inspection itself, covered in our page on the customs inspection at your company. It deals with the moment that follows, when the administration has finished investigating and announces what it intends to claim. It is, in our view, the most underestimated moment in the entire customs procedure.
1. Two regimes, one principle
The Customs Code refers to two sets of rules depending on the nature of the charge (Art. L. 311-1, formerly Art. 67 A). Where the chargeable event for the duties and taxes is the importation or exportation of goods, the prior adversarial exchange is governed by the Union Customs Code (Regulation (EU) No 952/2013). This is the case for customs duties, whatever the ground for the reassessment: tariff classification, value, origin. Where the chargeable event is something else, which covers excise duties in particular, any finding that may lead to an assessment gives rise to an exchange organised by the national Code itself (Art. L. 311-3 to L. 311-9).
Same principle. Before any adverse decision, the person concerned must know the grounds on which the administration intends to rely and be able to respond within a set period. The procedures differ, and one must know which regime applies before writing the first line.
Certain decisions are outside the exchange. The national Code excludes the decision to carry out an inspection, the decision leading to notification of an offence, measures taken to enforce a court decision and the issue of a notice of assessment (avis de mise en recouvrement, AMR) intended to recover claims unpaid on the due date, except where they were established following an offence (Art. L. 311-2). The Cour de cassation likewise holds that no prior exchange is required where the administration does not challenge the duties declared and merely recovers what has not been paid (Cass. com., 24 January 2024, no. 22-13.103, published). Delegated Regulation (EU) 2015/2446, for its part, lists in Article 10 a few cases in which the right to be heard does not apply, unrelated to an ordinary reassessment.
2. What the communication must contain
For customs duties, Implementing Regulation (EU) 2015/2447 sets out the content of the communication of grounds (Art. 8(1)). It must refer to the documents and information on which the authorities intend to base their decision. It must state the period within which the person may express a point of view, running from the date on which the person receives or is deemed to have received the communication. Finally, it must refer to the right of access to those documents and information.
For other charges, the person liable is informed of the grounds and the amount of the proposed assessment (Art. L. 311-3). If that person asks for a written communication, the administration sends a reasoned assessment proposal enabling observations to be made or acceptance to be notified, within thirty days (Art. L. 311-7). The administration must also inform the person of the points examined that contain no error or shortfall, which matters for what follows.
The first reading, then, is a checking exercise. Are the documents identified, or does the administration refer to “the investigation” without further detail? Is the time limit stated? Is the right of access mentioned? The Cour de cassation checks that the person liable was informed of the right to access the documents on which the administration relies, and considers that it is then for that person to exercise it (Cass. com., 17 June 2026, no. 25-10.751, published). A defective communication is not a gift to be saved for litigation, and it is a common mistake to rejoice about it in silence, telling oneself that the irregularity will bring down the reassessment two years later, when the case law of both the Court of Justice and the Cour de cassation requires the company to have done what was necessary to obtain the documents and to show how their absence actually deprived it of an argument. The missing documents must be requested immediately, in writing.
The procedural argument has its limits in any event. The Court of Justice accepts that a breach of the right to be heard leads to annulment of the decision only if, had it not been for that irregularity, the procedure could have resulted in a different outcome (CJEU, 3 July 2014, Kamino International Logistics and Datema Hellmann, C-129/13 and C-130/13). It is better to obtain the documents during the exchange than to argue two years later that one would have said something different had one had them.
3. The trap of the immediate response
The implementing regulation provides for an accelerated procedure, during the examination or inspection itself, where the administration intends to base its decision on certain results: examination of goods presented, verification of the declaration, post-release control concerning goods still under customs supervision, verification of proof of customs status or origin (Art. 9(1) of Regulation 2015/2447). In that context, the person may either express a point of view immediately, by the same means as was used for the communication, or require a written communication in accordance with Article 8, with the thirty-day period (Art. 9(2)), except where the decision concerns goods for which no declaration has been lodged. The authorities must inform the person of these two options, and they record whether the person chose to respond on the spot (Art. 9(3)).
The national Code has the same mechanism for other charges. Where the exchange takes place orally, the person liable is informed that a written communication may be requested (Art. L. 311-4), and the oral communication is recorded, which establishes, unless proven otherwise, that the administration allowed the person to submit observations and informed the person of the possibility of a written procedure (Art. L. 311-6). In the case of an inspection of goods in transit, the written procedure is available only once the amount of the proposed assessment has been guaranteed (Art. L. 311-5).
Our advice is clear. In writing, almost always. Except in exceptional situations (perishable goods held up, an obvious clerical error that can be corrected on the spot), the written communication should be requested. Responding immediately means giving up thirty days of preparation, access to the file and the opportunity to quantify one’s own position, in exchange for a saving of time that mainly benefits the administration. A form ticked in haste at the counter, or a remark made orally to an officer on a quayside, is enough to exhaust the right to be heard.
4. Thirty days: how to use them
The standard period is thirty days (Art. 8(1) of Delegated Regulation 2015/2446; Art. L. 311-7 of the Customs Code). The delegated regulation provides for a single derogation: where the decision concerns the control of goods for which no declaration has been lodged, the administration may require a reply within twenty-four hours (Art. 8(2)). The starting point is actual or deemed receipt of the communication. The date of the registered letter counts, and it must be noted the same day.
First week: the file. The request for access to documents should be sent without delay, in writing, referring to the documents mentioned in the communication and requesting all those on which the administration bases its position: verification report, reply from the foreign authorities, laboratory analyses, official customs reports (procès-verbaux), exchanges with the supplier. The texts provide for no automatic extension of the period if the administration is slow to send them; that is one more reason to ask early, and to keep a record of every reminder.
The trap of the Grasse email comes down to one rule. Where the person expresses a point of view before the period expires, the administration may adopt its decision, unless the person at the same time indicates an intention to continue expressing views within the set period (Art. 8(2) of Regulation 2015/2447). Any partial reply, any initial letter sent to “register disagreement”, must therefore end with a sentence expressly reserving the right to supplement the observations until the end of the period. One line is enough. It changes everything.
Conversely, there is no advantage in letting the period run out. The administration loses nothing by waiting: the communication of grounds suspends the limitation period for the debt until the end of the period given for replying (Art. 103(3)(b) of the Union Customs Code; for other charges, Art. L. 311-9 of the Customs Code). Silence is an answer. The worst one. At the end of the thirty days, the administration decides, with or without observations (Art. L. 311-8).
5. What should be written?
The reply to a communication of grounds is not a letter of protest. It is the first step in possible litigation, and it must be drafted as such, because everything in it will be reread by the regional director dealing with the challenge, then by the judicial court (tribunal judiciaire), and anything not in it will be harder to have accepted later, since the administration never fails to point out that an argument presented late could have been raised during the exchange if the company had believed in it.
The structure that works is simple. First the facts, as the company establishes them, operation by operation, with the corresponding documents. Then the law: the text the administration applies, its reading of it, the reading the company puts forward, with the relevant case law. Then the figures, proposing an alternative calculation where appropriate, because an administration that sees its own calculation contradicted by a precise table is more inclined to revise its position than to defend an overall amount. Finally, a clear request: withdrawal of the reassessment, reduction to a quantified amount, or failing that, consideration of specific points.
Three mistakes recur constantly. The first is to admit facts in order to appear cooperative, for example by writing that the company “should have checked” the origin declared by its supplier; such a sentence will be quoted in the notice of assessment and, where applicable, before the criminal court. The second is to widen the debate, by spontaneously mentioning other operations or suppliers the administration has not targeted, by attaching internal tables covering a longer period than the inspection, or by explaining, to demonstrate good faith, that the same practice has been followed for ten years with all the group’s suppliers, which amounts to handing the administration, on a plate, the material for a second reassessment. The third is to entrust the reply to someone who has not read the file. The customs broker knows the declarations; it does not always know the contracts, and it is not for the broker to decide what the company admits or disputes.
In the Grasse case, the right reply would have started with a request for access to the verification report and the foreign authorities’ reply, sent on 3 July. It would have continued, if an initial position seemed useful, with a letter expressly reserving the right to supplement the observations. It would have ended, before 1 August, with full observations: discussion of the scope of the foreign authorities’ reply, the supplier’s documents, an analysis of good faith with a view to possible remission of duties. Nothing impossible in thirty days.
6. After the exchange: decision, recovery, challenge
At the end of the exchange, the administration takes its decision. Where it rejects the observations of the person liable, its reply must state reasons (Art. L. 311-8). For customs duties, an adverse decision must set out its grounds and refer to the right of appeal provided for in Article 44 of the Union Customs Code (Art. 22(7)). It is useful to compare the reasons given in the final decision with the observations: a specific argument left unanswered weakens the decision, and it is often these silences that the court picks up.
The duties are then recovered by a notice of assessment. A challenge is addressed to the authority that issued it within three years of its notification (Art. L. 331-1), then brought, where appropriate, before the judicial court within two months of the reply or of the expiry of the six-month period available to the regional director (Art. L. 332-2). The observations submitted during the exchange then form the natural basis of the challenge, which is a further reason to take care over them.
One final observation. The adversarial exchange is the only moment in the procedure when the company speaks to those who conducted the investigation, before their position is fixed in a decision that their superiors will then have to defend. Reassessments that collapse or are sharply reduced most often do so at this stage, not before the court, because the officers who conducted the investigation know the weaknesses of their file better than anyone, they can still correct a calculation, drop a series of operations or accept a new document without having to go back on their word publicly, and a serious, documented, quantified reply gives them precisely the means to do so before their own superiors, which no court decision delivered three years later will allow any more. Thirty days is short. It is also the best lever the company has.
The firm drafts observations in reply to communications of grounds and assessment proposals, and assists companies in obtaining access to the file and in discussions with the investigation services. Hervé Guyader is co-author of the Guide Lamy des procédures douanières, whose update following the recodification of 1 May 2026 is under way. For an overview of all our work, see our page customs lawyer in Paris; for a current matter, contact the firm, with a reply within 24 business hours.
On the same path: what to do during a customs inspection at your company; challenging an official customs report; limitation of the customs debt; Binding Tariff Information and challenging the classification.
If the matter turns into a reassessment, see our page on challenging a French customs reassessment.
This analysis is part of the firm’s work in international trade law.
Frequently asked questions
How long do I have to reply to a communication of grounds from customs?
Thirty days from its actual or deemed receipt (Art. 8 of Delegated Regulation (EU) 2015/2446 for customs duties; Art. L. 311-7 of the Customs Code for other charges). By way of exception, the administration may require a reply within twenty-four hours where the decision concerns goods for which no declaration has been lodged.
Can customs decide before the thirty days are up?
Yes, if you have already expressed your point of view without indicating that you intended to supplement it. Implementing Regulation (EU) 2015/2447 allows this (Art. 8(2)). Any partial reply must therefore expressly reserve the right to supplement the observations until the period expires.
Am I entitled to consult the customs file?
Yes. The communication must refer to the documents and information on which the administration intends to base its decision and to your right of access to them (Art. 8(1) of Regulation 2015/2447). The Cour de cassation checks that this information was given and considers that it is then for the person liable to exercise that right (Cass. com., 17 June 2026, no. 25-10.751). Request the documents in writing on receipt.
Should I answer the officers orally during the inspection?
It is better to request a written communication. Where the communication is made during the examination, you may express your point of view immediately or require a written communication with a thirty-day period, except for undeclared goods (Art. 9 of Regulation 2015/2447; Art. L. 311-4 of the Customs Code). Responding on the spot exhausts the right to be heard without access to the file.
Is an adversarial exchange always mandatory?
No. It is not required, in particular, for the decision to inspect, the notification of an offence or a notice of assessment that merely recovers claims unpaid on the due date (Art. L. 311-2 of the Customs Code; Cass. com., 24 January 2024, no. 22-13.103). It becomes mandatory again where those claims were established following an offence.
References: Union Customs Code (Regulation (EU) No 952/2013 of 9 October 2013), Art. 22(6) and (7), Art. 44, Art. 103(3); Delegated Regulation (EU) 2015/2446 of 28 July 2015, Art. 8 and 10; Implementing Regulation (EU) 2015/2447 of 24 November 2015, Art. 8 and 9; Customs Code, Art. L. 311-1 to L. 311-9, L. 331-1, L. 332-2, in force since 1 May 2026 (Ordinance No. 2026-265 of 8 April 2026); CJEU, 3 July 2014, Kamino International Logistics and Datema Hellmann, C-129/13 and C-130/13; Cass. com., 24 January 2024, no. 22-13.103, published in the Bulletin; Cass. com., 17 June 2026, no. 25-10.751, published in the Bulletin; Doctrine: Guide Lamy des procédures douanières, Wolters Kluwer, co-authored by Hervé Guyader (update in progress).