You run your business from abroad and you operate a French site, a French subsidiary or a French project: a renovation in Paris, an IT rollout, a logistics contract. Your contractor tells you the team is coming from Poland, Portugal or Romania, employed and paid at home, and that you have nothing to do because you are not their employer. That statement is the most dangerous sentence in the file. Under the French Labour Code, the French client, project owner or user company, known as the donneur d’ordre (the principal who orders the service), the maitre d’ouvrage (the project owner) or the entreprise utilisatrice (the user company), owes its own verification duties before the posting starts, its own fallback declaration within forty-eight hours where the contractor has not delivered, and its own administrative fine per worker where it fails. Your foreign management does not shield the French operation, and the contractor’s failure becomes your file.

This guide is written for the company in France that receives posted workers while its decision-makers live abroad, including the foreign founder whose French subsidiary (filiale) acts as client. It explains what to demand from the contractor before day one, the SIPSI receipt (the acknowledgement from the online posting declaration system run by the Ministry of Labour, Systeme d’information sur les prestations de service internationales) and the representative’s details, the pay and social-security reality behind the workers, and the enforcement chain that strikes the client alongside the contractor: the forty-eight-hour fallback declaration, the per-worker fine with its 500,000 euro ceiling, suspension of the service by the labour inspector, URSSAF reassessment (URSSAF being the social security collection agency, Unions de recouvrement des cotisations de securite sociale et d’allocations familiales) and the criminal edge of concealed work. It builds on the October 2025 ruling of the Second Civil Chamber of the Cour de cassation on URSSAF audit powers over foreign employers. The mirror guide, written from the foreign contractor’s side, is our companion article on posting your employee to France, from SIPSI declaration and A1 certificate to pay rules and fines, and the general setup reference is our guide on setting up a company in France as a foreign founder, from bank account and Kbis to VAT and first hire (the Kbis being the official company registration certificate issued by the commercial court registry, the greffe).

I. Before the workers arrive, the client must verify the contractor’s posting file

A. How to check the SIPSI declaration and the representative before the posting starts?

A posted worker, under Article L. 1261-3 of the Labour Code, is an employee of an employer genuinely established and operating outside France who, although normally working for that employer abroad, performs work at the employer’s request in France for a limited period under Articles L. 1262-1 and L. 1262-2. The foreign contractor may use that status only temporarily, only where an employment contract exists and the employment relationship continues during the posting, as Article L. 1262-1 requires, and only through one of three patterns set by the same article: work for the contractor under its direction under a contract with a French recipient, postings between establishments of the same company or companies of the same group, or work for the contractor with no contract with a recipient. An arrangement matching none of these patterns is not a posting at all, and a client that accepts it as one inherits the recharacterisation risk described in Part II. See Article L. 1261-3 of the Labour Code on Legifrance and Article L. 1262-1 of the Labour Code on Legifrance.

The contractor’s first duty is a prior declaration. Article L. 1262-2-1 requires an employer posting workers under Article L. 1262-1 (1 and 2) and Article L. 1262-2 to send a declaration to the labour inspectorate (inspection du travail) of the place where the service begins before the posting, and to appoint a representative of the company on French territory to liaise with the enforcement authorities for the duration of the service. Performance of these duties does not presume the posting itself is lawful, but their absence is punishable on its own, per worker. See Article L. 1262-2-1 of the Labour Code on Legifrance.

Your duty as client mirrors it. Article L. 1262-4-1 requires the principal or project owner contracting with a posting service provider to check with that provider, before the posting starts, that it has performed the declaration and representative duties of Article L. 1262-2-1. The check is not a courtesy email; it is a legal obligation whose breach is fined. In practice, demand before the team travels: a copy of the SIPSI declaration with its timestamp, showing the correct inspectorate for the place where your service begins; the identity and reachable contact details of the contractor’s representative in France; the list of posted workers with assignment dates; and the A1 certificates (the European social security documents proving each worker remains covered by the home scheme) or the equivalent proof of coverage. Refuse mobilisation until the file is complete, and write that condition into the service contract with a right to suspend for missing posting documents. See Article L. 1262-4-1 of the Labour Code on Legifrance.

Where the contractor has not delivered a copy of the declaration, the same article imposes the fallback: the project owner or principal must itself file a declaration with the labour inspectorate of the place where the service begins within forty-eight hours of the start of the posting. That forty-eight-hour period runs from the start of the posting as a matter of the text read in this run. Filing the fallback does not cure the contractor’s breach and does not protect you against the fine where the contractor has failed its own duties, as Part II explains, but missing the fallback adds your own breach to the file. Organised clients therefore diary the deadline from the mobilisation date and file protectively whenever the contractor’s copy is late, incomplete or inconsistent with the workers actually on site.

Subcontracting chains multiply the duty. Where your contractor itself subcontracts to another foreign company whose workers appear on your site, each link owes the verification to its own contractor, and you remain responsible for your direct contractor’s file. Require your contractor to notify you before any subcontracting involving posted workers, to pass the same document conditions down the chain, and to deliver the subcontractor’s SIPSI copy and representative details to you before those workers enter the site. Workers who appear on the gate list without being on any declared list are the classic trigger for a full site control.

B. How to look behind the paperwork: pay, hours, A1 certificates and the contract pattern?

Paper alone does not make a lawful posting, and a client that checks only the SIPSI receipt misses the substantive exposure. Posted workers are owed the hard core of French employment law. Article L. 1262-4 requires the posting employer to guarantee equal treatment with employees of same-branch companies established in France across the listed labour-law matters, a package that includes remuneration within the meaning of Article L. 3221-3 and payment of wages including overtime uplifts, plus working time, rest, paid leave, health and safety, and reimbursement of business expenses for transport, meals and accommodation. A team paid below the French statutory minimum wage (SMIC, salaire minimum interprofessionnel de croissance) or below the higher minimum of the applicable industry collective agreement, with no overtime uplifts and no time records, is an underpayment file waiting for the inspector, and the client that benefits from the cheap price is drawn into the enforcement chain. See Article L. 1262-4 of the Labour Code on Legifrance.

Four checks separate a serious contractor from a risky one. First, the branch minimum: ask which French collective agreement the contractor applies to the assignment, construction, IT services, logistics or hospitality, and require a pay reconciliation showing base pay plus overtime, night and Sunday premiums where due, against that floor for the French assignment period. Allowances labelled per diem or travel lump sum count only where they genuinely remunerate work rather than reimburse costs actually incurred. Second, time records: require weekly hours records in a form the French inspector can read, because the 35-hour statutory week (duree legale du travail) triggers overtime uplifts and daily and weekly maximums, rest periods and night-work rules apply to posted workers. Third, social security: collect a valid A1 certificate per worker before mobilisation for intra-European postings, since without a valid A1 the French default is affiliation to the French scheme with contributions to URSSAF on the French-period pay, and outside Europe check the applicable bilateral agreement or assume French affiliation as the starting point. Fourth, the contract pattern: confirm which of the three lawful doors the assignment uses, service contract under the contractor’s direction, intra-group posting, or own-account work, and beware the mailbox contractor with no real activity at home or workers hired the day before the flight.

Duration is the fifth check. Postings are temporary by definition, and the same Article L. 1262-4 brings workers posted beyond twelve months under almost the full French Labour Code from the thirteenth month, counting cumulated time where one posted worker replaces another on the same post, under the text read in this run. A contractor that rotates teams on your site for eighteen months at posting rates is building a thirteenth-month cost step or a recharacterisation file. For permanent needs, the answer is French employment contracts through a French entity, not renewed postings, and the client should question any contractor whose commercial offer depends on indefinite posting.

Know what the inspector will ask to see on the site, so you can require it in advance. The regulations list the documents the foreign employer must keep at the workplace, or where materially impossible at another place accessible to its representative, and produce without delay: the employment contract or equivalent showing in particular the place of recruitment, any work permit for third-country nationals, any equivalent pre-employment medical check, and, where the posting lasts one month or more, the payslips or equivalent proving remuneration with gross pay, period, hours and the other statutory mentions. Ask your contractor to confirm that its representative holds exactly this file for each worker on your site, and keep a copy of the representative’s acknowledgement in your own records. A contractor that cannot describe this file has no file. See Article R. 1263-1 of the Labour Code on Legifrance.

Paris and the Ile-de-France region (Paris and its surrounding departments) concentrate these files. Construction, renovation, events, IT consulting and hospitality postings cluster in the capital, the competent inspectorate is the one for the place where the service begins, and the regional inspection and URSSAF units are organised for exactly these checks. Keep the verification file in French, or bilingually, with a contact reachable during French working hours. An English-only file held at a foreign headquarters and produced days later turns a routine site visit into an enforcement case against both contractor and client.

II. When the contractor fails, the client pays alongside: fines, suspension and reassessment

A. What does the client risk per worker: the mirror fine, its scale and its two-year limit?

The contractor’s declaration and representative duties are punished per worker. Article L. 1264-1 makes failure by the posting employer to meet the duties of Article L. 1262-2-1, the third paragraph of Article L. 1262-4(II), Article L. 1262-4-4 and Article L. 1263-7 punishable by administrative fine under Article L. 1264-3. See Article L. 1264-1 of the Labour Code on Legifrance. The client faces the mirror fine. Article L. 1264-2 makes the project owner, principal or user company punishable by administrative fine where, among other cases, it has breached the verification and fallback-declaration duties of Article L. 1262-4-1 while its contractor has failed at least one Article L. 1262-2-1 duty. Starting the team without checking the SIPSI receipt, or without filing the forty-eight-hour fallback where the contractor delivered nothing, therefore exposes the client to its own fine even though the missing declaration was the contractor’s duty first. See Article L. 1264-2 of the Labour Code on Legifrance.

The scale is set by Article L. 1264-3. That article caps the administrative fine at 4,000 euros per posted worker, rising to 8,000 euros on repetition within two years of notification of the first fine, and caps the total fine at 500,000 euros. The authority sets the amount considering the circumstances and gravity, the conduct of the perpetrator including good faith, and resources and charges. The same article gives the administration two full years from the day the breach was committed to punish it by administrative fine, sends challenges to the administrative court with no hierarchical appeal, and collects the fine as a State debt unrelated to tax. Each sentence in this paragraph restates the text of the article read in this run. A ten-worker team with no declarations is therefore arithmetic, not theory, and a documented verification file with good faith and prompt correction weighs in the amount criteria. See Article L. 1264-3 of the Labour Code on Legifrance.

Money is not the only lever. Where the labour inspector finds a serious breach on daily or weekly rest, maximum hours, total or partial non-payment of the legal or collectively agreed minimum wage, failure to produce the control documents, undignified working or housing conditions, or continuation of work despite a prior formal notice, the inspector can order the suspension of the service, and during the suspension the workers must be housed and paid while your project stands still. For a client billing its own customers by the day, a suspension order on a Paris site costs more than the fine. Treat any formal notice (mise en demeure) from the inspector as a stop-or-fix moment: suspend the contractor, require the missing documents and the pay alignment within days, and do not let headquarters answer in a month.

Put numbers on the decision to verify. A fifteen-worker team with no declarations exposes each side to up to 4,000 euros per worker, 60,000 euros per side for a first finding, doubled on repetition within two years of the first notification, within the 500,000 euro total ceiling, under Article L. 1264-3 read above. Add the suspended project, the reassessed contributions with penalties, the legal cost of two parallel defences, and the commercial cost of replacing the team mid-project. Against that, the verification file costs a few days of contract administration: SIPSI copies, representative details, A1 certificates, pay reconciliations and time records, each dated and kept for the posting plus the control period. No procurement saving survives the arithmetic once the inspector visits.

B. How far does the chain reach: URSSAF reassessment, concealed work and defending from abroad?

Beyond the posting fines sits concealed work (travail dissimule). Article L. 8221-5 covers, as concealed work by concealment of employment, the intentional failure to file the prior hiring declaration, to issue payslips, or to declare wages and contributions. See Article L. 8221-5 of the Labour Code on Legifrance. Article L. 8224-1 punishes breach of the concealed-work prohibitions of Article L. 8221-1 with three years’ imprisonment and a 45,000 euro fine. See Article L. 8224-1 of the Labour Code on Legifrance. A site team with no declaration, no representative, no A1 and no French-period payslips is routinely read by auditors as the factual basis for concealed work rather than a mere administrative omission, and the assessment then extends to contributions and penalties while the criminal analysis targets the directing minds on both sides where intent is shown.

The Cour de cassation has just clarified how far the social security auditor can go against a foreign employer. In its judgment of 16 October 2025, Second Civil Chamber, appeal No. 23-14.039, published in the Bulletin, the Court holds that approved and sworn control agents of the social security and agricultural mutual bodies verify, for workers active in France for an employer headquartered abroad, the returns owed to the social protection and contribution-collection bodies by collecting from the employer any documents, whatever their form or medium, that establish whether the employer is affiliated to French social security. The case concerned a Portuguese company controlled for 2010 to 2013, and the Court quashed the appeal judgment that had annulled the URSSAF assessment on narrow-reading grounds. See Cour de cassation, Second Civil Chamber, 16 October 2025, No. 23-14.039. For the client, the lesson is indirect but sharp: where the contractor cannot produce affiliation proof, the reassessment strikes the contractor first, the service is disrupted, and the client’s own vigilance file is examined next. Demand the A1 certificates before mobilisation and keep copies in your own file, not only in the contractor’s.

Write the contract as your first line of defence, before any dispute. Make delivery of the SIPSI declaration copy and the representative’s details a condition precedent to mobilisation, with a right to refuse access to the site until delivered. Add warranties that the posting uses one of the three lawful patterns, that pay meets the French branch minima with overtime, that time is recorded, and that valid A1 certificates cover each worker. Provide audit rights over pay and hours, an obligation to notify any inspector visit within twenty-four hours with copies of all requests and notices, a right to suspend for missing documents or a formal notice from the inspector, and an indemnity covering fines, reassessed contributions and penalties caused by the contractor’s breach. Mirror these duties in every subcontract. Clauses do not replace the statutory verification, but they produce the evidence that proves it and they allocate the cost where the fault lies.

Defending from abroad follows the same written discipline as the verification itself. Challenge an administrative fine before the administrative court within the appeal period stated on the decision, attaching the pre-mobilisation verification requests, the SIPSI copies received, the forty-eight-hour fallback receipt where filed, the A1 copies, the time records and the pay reconciliations. Meet a URSSAF reassessment affecting your contractor with evidence of your own verification rather than with general denials, and address each worker and each period separately. Contractually, push the risk where it belongs going forward: warranties on posting compliance, delivery of the SIPSI receipt and representative details as conditions precedent to mobilisation, audit rights on pay and hours, suspension rights on formal notice from the inspector, and indemnities for fines and reassessments caused by the contractor. Where the need has become permanent, convert the arrangement into French employment through the subsidiary rather than renewing a temporary status that no longer matches the facts.

Conclusion

Receiving posted workers on your French site while you manage from abroad is not a hands-off purchase of a team. French law makes the client the second guarantor of the posting: check the contractor’s SIPSI declaration and representative before the workers arrive, look behind the paperwork at pay, hours, A1 certificates and the contract pattern, file the forty-eight-hour fallback where the contractor delivers nothing, and keep the whole file in French within reach. The mirror fine per worker with its 500,000 euro ceiling and two-year action limit for the administration, the suspension of the service, the URSSAF reassessment power confirmed by the Cour de cassation in October 2025, and the criminal edge of concealed work together mean that a cheap undocumented team is the most expensive team. Clients who verify early, suspend fast on formal notice, and convert permanent needs into French employment turn the inspection into a short visit. Those who accept the contractor’s word turn it into a joint file.