Germany is the fifth-largest source of posted workers into Belgium and the second-largest supplier of posting companies in metalworks and pipefitting. German industrial contractors, plant builders and installation specialists are a constant presence on Belgian sites, and the compliance profile is different from the construction-heavy Polish or Portuguese pattern: fewer, longer, more technical assignments, often on high-value industrial sites.
Where Germany sits in the Belgian market
German companies filed for 18,738 posted persons into Belgium in 2023, 8.1 percent of the Limosa total, a share that has held steady for several years. German firms are 17 percent of posting companies in metalworks and pipefitting, 14 percent in electrical installation and assembly and 12 percent in the petrochemical industry. In construction proper the German share is smaller, which reflects a workforce weighted towards industrial and technical trades rather than general building.
German search behaviour reflects this. Interest in Belgian posting compliance is lower in volume than in Poland or Romania, but the commercial value per query is the highest of any market we measured, which fits a profile of fewer companies making larger, more considered decisions.
The four things you must have
Work backwards from your mobilisation date, because two of these depend on third parties.
1. A1 certificates, applied for at the employee’s health insurance fund (Krankenkasse), with DVKA as the liaison body before departure, one per posted worker, covering the full planned period. They prove your people stay in the German social security system rather than becoming liable for Belgian contributions. See what Belgian inspectors check on an A1. 2. A Belgian company number (CBE) and portal access, if Check-in-at-Work will apply. Foreign employers need both to register presence at all, and this is the step most often left too late. 3. The Limosa declaration, filed at limosa.be before the first day of work. It produces a LIMOSA-1 receipt each worker must be able to show to the Belgian client. Full detail in our Limosa guide. 4. A liaison person, whose identity and contact details you give to the Belgian Labour Inspectorate, and who can actually be reached about the posting.
Does the A1 replace the Limosa declaration?
No, and this is the most expensive misunderstanding in cross-border work.
The A1 answers which country’s social security system applies. Limosa answers whether Belgium knows your worker is on its territory. They are issued by different bodies for different purposes. An employer holding a valid A1 still has to file a Limosa declaration before the work starts, and an inspector will ask for both.
The Montagerichtlinie assumption and the 8-day limit
German plant builders and equipment suppliers frequently rely on the idea that assembly and commissioning of their own supplied goods is exempt. In Belgium there is such an exemption, and it is real, but it is capped at 8 days and limited to qualified or specialised workers performing the initial assembly or installation of goods the company supplied.
That cap is absolute. A commissioning problem that pushes the job to day nine does not shorten the exemption, it removes it, and you are then in the position of having failed to file a required declaration for the whole period. Given that industrial commissioning routinely overruns, the safe practice for German suppliers is to file the Limosa declaration as standard and treat the exemption as a fallback you never rely on.
A second point specific to German employers: the A1 is issued by the employee’s own Krankenkasse, not by a single central body, so a crew drawn from several health insurance funds means several parallel applications. Start early, and check that every certificate has actually arrived before mobilisation rather than assuming a batch request was processed as one.
When does Check-in-at-Work apply?
Registration is mandatory for works on immovable property, excluding cleaning, and for certain meat-sector activities, where the total value of the works reaches 500,000 euro excluding VAT. The threshold applies whether that value is reached at the start of the works or during them, and it attaches to the works as a whole, not to your own contract value.
Three points that catch foreign contractors:
- It is daily. Registration must happen before the person begins work, every working day, for every person on site. It is not a one-off enrolment.
- Responsibility is shared. It lies both with the party sending the worker and the party doing the work, and the two must agree who registers and verify it happened. Assuming the main contractor covers you is not a defence.
- “Works on immovable property” is broad, reaching well beyond new-build into renovation, fit-out, technical installation and groundworks.
From 1 April 2027, a Programme Law adopted on 30 May 2026 extends the obligation to registering both entry and exit, and brings the supply of ready-mixed concrete into scope. Sign-in sheets will not carry you past that date.
The differences between the systems are set out in Limosa, Dimona or Check-in-at-Work.
What it costs to get wrong
Failing to file a Limosa declaration is a level 4 offence, the heaviest category in the Belgian Social Criminal Code, carrying the possibility of imprisonment alongside financial penalties.
Fines rose on 1 February 2026, when the Act of 19 December 2025 raised the multiplier applied to social criminal fines from 8 to 10. For some infringements the amount is multiplied by the number of workers involved, up to a maximum of 100, which is what turns one administrative gap on a ten-person crew into a serious figure.
There is a commercial cost too. Your Belgian client is exposed through joint and several liability for your workers’ wages, and through the withholding obligation: where a contractor has social or tax debts, the client must withhold 35 percent of each invoice excluding VAT for social security debts and 15 percent for tax debts, checked at checkinhoudingsplicht.be. Since 1 May 2026 a further 15 percent applies for outstanding self-employed contributions. A subcontractor who creates that problem does not get invited back. Our guide for main contractors covers what a Belgian client has to verify about you.
Keeping the paperwork and the site in agreement
The hard part of cross-border work is not understanding the rules. It is keeping the file in your home office and the reality on a Belgian site aligned, week after week, as crews rotate and programmes move.
Two habits do most of the work. Treat every crew change as a compliance event: a new person means a new A1 check, a new Limosa entry and site registration under their own identity, arranged before they travel. And capture presence digitally at the moment someone arrives, tied to the person and the project, so the site record matches your declarations by default and you can produce a specific past day on request without reconstructing it.
Suivo’s check-in-at-work is used on Belgian sites where several subcontractors work side by side, and runs on the same workforce management platform as time tracking, so the data you capture for compliance also feeds hours and project costing instead of sitting in a separate system.
See how Cibor manages registration across Belgian sites.
A note on language
German is an official language of Belgium, but only in the German-speaking Community in the east of Wallonia. On the great majority of Belgian sites, the working and administrative language will be Dutch or French. Do not assume German-language correspondence will be accepted.
The full set of Belgian obligations, country by country, is collected in our reference guide for employers posting into Belgium.
Book a free demo
If you are bringing German crews onto Belgian sites and want presence registration that satisfies an inspector without slowing your work down, we will show you how it runs day to day. Book a free demo.
