Posted Workers · Cross-border Compliance
One trip, four regimes: the A1, the posting notification, and the work permit.
A single cross-border assignment engages up to four independent bodies of law, each with its own question, authority and filing. Most compliance failures in business travel arise not from ignorance of the rules but from category error. This article separates the regimes and sets out the assessment sequence that resolves the standard cases.
The Four Regimes
Four questions, four authorities, four filings.
Social security
A1 certificate
Which single system covers the worker?
Reg. (EC) 883/2004, 987/2009
Home state issues; host must accept.
Labour law
Posting notification
Which working conditions apply; is the host informed?
Dir. 96/71/EC, 2018/957, 2014/67/EU
Host state receives, before work begins.
Immigration
Work permit / visa
May the person work on this territory?
National law; free movement; Van der Elst.
Host state authorises.
Tax
No certificate
Where does the income become taxable?
Bilateral treaties; OECD Model.
Facts decide; no filing warns you.
A filing under one regime proves nothing under another. That proposition resolves most of the confusion in this field.
01 · Social Security
The A1 attaches to work, not to duration.
The A1 certificate certifies that a worker temporarily active in another EU/EEA state or Switzerland remains subject to the home state's social security legislation. The obligation attaches to work, not duration: Regulation 883/2004 contains no de minimis, so on the strict reading even a one-day working visit is within scope.
Two bases matter in practice. Article 12 (posting): a worker sent to one state for an anticipated duration of up to 24 months, provided the employer ordinarily carries out substantial activities in the sending state and the worker does not replace another posted person. Article 13 (multi-state work): a worker regularly active in two or more states — one certificate, ordinarily renewed annually, covering all of them. For the frequent traveller, Article 13 is usually the accurate description of the work pattern and the lighter administrative path.
Danish employers apply through Udbetaling Danmark via virk.dk; the published processing target for single-state postings is approximately five weeks. The certificate need not precede departure as a matter of EU law: the Court of Justice has held that an A1 may be issued retroactively and, once issued, binds the institutions and courts of the host state (C-527/16 Alpenrind). The defensible standard: apply before departure, carry the application receipt, and treat retroactivity as a cure — not a plan.
02 · Labour Law
One directive, thirty national machines.
The Directive fixes the trigger — the temporary provision of a service in another member state, whether to a client, within a group, or through an agency — but leaves the machinery national. The result is roughly thirty national systems across the EU, EEA and Switzerland, differing in portal, deadline, exemptions and sanction. See our EU-wide posting notification guide and the country-specific Denmark / RUT deep-dive for the operational detail.
Six systems, by way of illustration
Sweden
Portal: Arbetsmiljöverket register
Deadline: First working day; contact person in Sweden; proof to the customer.
Meetings & short visits: No general meeting carve-out.
Sanction: SEK 20,000 per breached obligation, up to three per posting.
France
Portal: SIPSI; representative in France
Deadline: Before work begins.
Meetings & short visits: Exemptions for short events (artists, athletes, seminars).
Sanction: Up to €4,000 per worker; up to €8,000 on repeat within 2 years; capped at €500,000.
Germany
Portal: Meldeportal, sectoral (AEntG/MiLoG sectors only)
Deadline: Before work begins.
Meetings & short visits: Internal activities (meetings, negotiations) generally outside scope if ≤14 consecutive days and ≤30 days per 12 months.
Sanction: Up to €30,000; up to €500,000 for the gravest substantive breaches.
Belgium
Portal: Limosa
Deadline: Before work begins.
Meetings & short visits: Business meetings ≤60 days/year, ≤20 consecutive days per meeting; initial assembly ≤8 days; urgent repairs ≤5 days/month.
Sanction: Administrative and criminal fines under the Social Penal Code.
Switzerland
Portal: Notification procedure (bilateral regime)
Deadline: 8 days in advance.
Meetings & short visits: Duty arises above 8 days/year — but from day one in seven listed sectors; 90-working-day annual ceiling.
Sanction: Fines; service bans for serious breaches.
Denmark
Portal: RUT
Deadline: At commencement; changes by next business day.
Meetings & short visits: Conference and business-travel exemptions; 8-day fitter rule.
Sanction: DKK 10,000; DKK 20,000 repeat.
Three structural points survive the variation. Exemptions for meetings and conferences are common but counted in days, and typically vanish in listed sectors. Several regimes narrow where third-country nationals are involved — the Netherlands expressly disapplies its exemptions for them. And the portals feed enforcement: what is filed, or not filed, is what the inspectorate sees before arriving.
03 · Immigration
Silent within the free-movement area — decisive outside it.
For EU, EEA and Swiss citizens working within that area, the regime is silent — free movement admits no permit requirement. It becomes decisive in two situations.
Third-country nationals within Europe. Under Van der Elst (C-43/93), a worker lawfully employed in one member state may in principle be posted to another without a further work permit; implementation, however, diverges. Germany requires a dedicated Van der Elst visa obtained in advance. France reaches the same outcome by the opposite mechanism — a work-permit exemption for workers lawfully employed in another member state, leaving only the SIPSI declaration and ordinary entry rules. Denmark sits at the restrictive end: third-country service providers generally require a Danish work permit, subject to narrow exemptions — the immigration fitter rule for specialised installation work (up to 90 days), business-travel and researcher exemptions (90 days), and, since 19 December 2025, a targeted exemption for event personnel at large closed international congresses.
Any travel outside the free-movement area. The question becomes the business-visitor line: attendance at meetings and conferences is generally permitted without work authorisation; productive work is not — and the host state, not the traveller's job title, draws the line. For third-country nationals, the Schengen 90/180-day limit adds an arithmetic constraint under which individually unremarkable trips can aggregate into a violation.
04 · Tax
The regime without a portal.
Tax issues no certificate and operates no register, which is why it is systematically forgotten. Two mechanisms belong in any assessment: the economic-employer analysis, under which host-state taxation can arise from day one where the worker's cost is borne by or recharged to a local entity — the standard configuration of an intra-group secondment; and permanent establishment, where a durable project or home-office pattern creates a corporate tax presence. Neither is excluded by remaining under 183 days.
The Assessment Sequence
Five questions, asked in order, resolve the standard cases.
- 01
Is work performed?
Activity, not title. If yes, the social security regime is engaged — always.
- 02
Is a service provided to a recipient in the host state?
If yes, the notification regime is engaged, subject to that state's exemptions. Purely internal attendance usually — not universally — falls outside.
- 03
What nationality?
EU/EEA/Swiss within the area: immigration silent. Third-country national: permit analysis first, and re-check the notification exemptions, several of which fall away.
- 04
How long, which sector?
Day-counts govern the exemptions; sectors govern whether exemptions exist. The operative durations compound across regimes: 8 days, 24 months, 12/18 months, 183 days.
- 05
One-off or pattern?
Recurring multi-state work points to Article 13 rather than per-trip filings, to aggregated day-counts in the notification regime, and to Schengen arithmetic in the immigration regime.
Applied to the standard cases: a one-day client meeting in Germany engages the A1 formally and nothing else. A three-week installation in Sweden requires the A1 and first-day registration, a contact person, and Swedish conditions on site. A six-month secondment to a French subsidiary requires an Article 12 A1, a SIPSI declaration, and a day-one tax analysis, the French entity bearing the cost. A multi-state sales director is an Article 13 case, with the meeting exemptions doing the work in the notification regime — Switzerland's day-counter being the exception to watch.
Recurrent Misconceptions
What HR teams believe, and what the law actually says.
“Under a week doesn’t count.”
Sweden, France, Austria and Denmark notify from day one; the A1 has no minimum anywhere.
“Intra-group is exempt.”
Intra-group posting is one of the Directive's three enumerated forms of posting (Art. 1(3)).
“We hold the A1, so we are covered.”
The A1 answers social security alone; the notification, permit and tax analyses are untouched by it.
“Remote work abroad is invisible.”
It engages social security at once, tax soon after, and in Belgium the notification duty as well.
“EU citizens never need anything.”
Free movement silences one regime of four; the sanctions in the other three fall on employers of EU citizens routinely.
Outlook
Coordination and digitisation; national obligations unchanged.
Enforcement is coordinating and the paperwork digitising, while the obligations remain national. The European Labour Authority now conducts EU-wide inspection campaigns; its June 2025 construction action week covered 137 companies across twelve member states, targeting non-genuine posting, bogus self-employment and illegal employment of third-country nationals.
On the legislative side, the Council and Parliament reached provisional agreement in June 2026 on a voluntary single digital declaration portal for postings — awaiting formal adoption, and years from displacing the national systems. The April 2026 provisional agreement on the revision of Regulation 883/2004 would, if adopted, exempt short business trips of up to three days within a 30-day window from the A1 requirement, construction excluded — a material simplification, but not yet law. And the ESSPASS pilots continue testing digitally verifiable A1s. The direction is uniform: more visibility for authorities, earlier.
The Dimmi Way
The trip is the unit of assessment.
The structural weakness this field exploits is organisational: the four regimes belong to four disciplines, four authorities and four deadlines, and in most organisations to nobody in particular. Dimmi makes the trip the unit of assessment — all four regimes evaluated from the facts of the assignment, each engaged filing prepared and submitted in the host state's format and deadline, and every certificate, threshold and day-count tracked across the workforce in one live view, with guidance source-linked to the instruments cited in this article.
Questions We Are Asked
What HR and mobility teams ask us.
Make every trip legible.
Book a 30-minute walkthrough. We assess a representative trip against all four regimes on the call, and show you the filings, the day-counts and the workforce view live.
Book a demoSources
European Commission: posted workers · Practical Guide on the applicable legislation · C-527/16 Alpenrind, EU:C:2018:669 · Udbetaling Danmark: social sikring ved arbejde i udlandet · Arbetsmiljöverket: report a posting · SIPSI · Limosa · Zoll: posting FAQ · SEM: notification procedure · Code du travail, art. R5221-2 · EPRS: posting of third-country nationals · Council: provisional agreement on the digital declaration system, 23 June 2026 · ELA: construction inspections 2025. Facts verified against the cited primary sources, July 2026. This article is general information, not legal advice; individual assignments should be assessed on their facts.