International Employment Contract: Secondment vs Expatriation

Sending an employee to work abroad seems straightforward on the surface. In reality, the choice between secondment and expatriation carries profound consequences for the employment contract, social contributions, personal tax and employer liability. Confusion between these two regimes can expose the company to URSSAF enforcement notices, double taxation and costly employment tribunal disputes. In 2026, with the strengthening of cross-border controls within the European Union and the generalisation of the directive on posting of workers (2018/957/EU), mastering these distinctions has become an absolute priority for HR and legal departments. This article compares point by point the two statuses, their social security regime, their tax treatment and the essential contractual precautions.

Secondment and expatriation: definitions and legal foundations

Before analysing the differences, it is necessary to set out precise definitions, as the boundary between the two regimes is regularly misunderstood in businesses.

Secondment: a link maintained with the original system

International secondment is the situation in which an employer temporarily sends an employee to exercise their activity in another country, while maintaining their original employment contract with the originating company. The seconded employee retains their affiliation to the social security scheme of their country of origin, subject to complying with the conditions provided for by the applicable European regulations or bilateral agreements.

In European law, regulation (EC) No 883/2004 on the coordination of social security systems provides that a seconded employee remains affiliated to the scheme of the sending Member State for a maximum period of 24 months, provided that:

• the foreseeable duration of secondment does not exceed 24 months;
• the employee is not sent to replace another seconded person;
• the employer carries on a substantial activity in the sending State (so-called "substantial activity" criterion).

This affiliation is evidenced by the A1 form (or E101 for certain third countries), issued by the social security body of the country of origin. This document is essential: in its absence, the employee may be required to pay contributions in the host country, giving rise to double contributions.

On the labour law front, directive 96/71/EC as amended by directive 2018/957/EU imposes the application to the seconded employee of a core of mandatory rights in the host country: minimum wage, maximum working hours, statutory paid leave, health and safety rules. Since 30 July 2020, if the secondment exceeds 12 months (extendable to 18 months on justification), the entire set of employment conditions in the host country becomes applicable, with the exception of rules on the establishment and portability of supplementary pensions.

Expatriation: a break with the original system

Expatriation is based on inverse logic. The expatriate employee is recruited locally or offered an expatriation contract which suspends or terminates their original employment contract. They leave the French social security scheme and join that of the host country. In France, the employer may nevertheless opt, with the agreement of the employee, for a voluntary continuation in the general scheme via the Caisse des Français de l'Étranger (CFE), subject to specific contributions.

Unlike secondment, no maximum duration is imposed on expatriation. The situation is designed to be long-term, often several years. The expatriate employee is subject to local labour legislation in its entirety, which requires an in-depth analysis of the labour law of the host country, particularly with regard to dismissal, end-of-contract compensation and union representation.

Social security regime: practical differences

Secondment: portability of social rights

The main advantage of secondment lies in the portability of social rights: the employee continues to accumulate pension rights in their original scheme, benefits from the health cover of their usual system (via the European Health Insurance Card within the EU) and contributes to ARRCO/AGIRC supplementary schemes if they are French.

For countries outside the EU, France has concluded more than 40 bilateral social security agreements (with the United States, Canada, Japan, Brazil, etc.) which organise similar mechanisms. In the absence of an agreement, the risk of double contribution is real: the employee and employer can be subject to tax in both states simultaneously.

Expatriation: local affiliation and protection to be rebuilt

In expatriation, the employee joins the local scheme, which means that their future rights depend on the generosity and stability of the foreign system. For destinations with weak social protection, subscription to the CFE and supplementary private insurance (medical guarantees, contingency) becomes essential. This additional cost can represent 10 to 20% of the total cost of mobility depending on the countries.

The administrative management of expatriation is also more cumbersome: the employer must ensure compliance with registration obligations with local social authorities, under penalty of sometimes significant sanctions. For HR teams managing multiple simultaneous mobilities, dedicated tools for managing international employment contracts allow centralising documents and securing each step of the process.

Taxation: tax residence, agreements and income taxation

The determining criterion of tax residence

In tax matters, the central concept is that of tax residence. Under French law, Article 4 B of the General Tax Code (CGI) considers as French tax residents persons who have in France their home or main place of residence, or whose main professional activity is exercised in France, or who have in France the centre of their economic interests.

An employee seconded for fewer than 183 days per year in a foreign country generally retains their tax residence in France and remains taxable there on all their worldwide income (subject to bilateral tax agreements). Conversely, an expatriate who actually transfers their home to the host country may lose their French tax residence, which has significant consequences: they are only taxable in France on their French-source income.

Bilateral tax agreements: anti-double taxation tool

France has signed more than 130 tax agreements designed to avoid double taxation. These agreements generally follow the OECD model and allocate the right to tax salaries to the state where the activity is exercised, unless the employee is tax resident in the other state, does not stay there more than 183 days and is remunerated by a non-resident employer.

For short secondments (less than 183 days), the agreement often maintains taxation in France. For long-term expatriates, it transfers taxation to the host country. However, some agreements provide for specific provisions on pension schemes, stock options or passive income that complicate the analysis.

Practical implication for the employer: the mission letter and remuneration package

In practice, the employer must carefully structure the international remuneration package: maintenance of basic salary, expatriation allowance (often 10 to 15% of gross salary), accommodation, school fees, annual return ticket. Each item has different tax treatment depending on whether it constitutes a reimbursement of professional expenses or a taxable benefit in kind.

The management of these complex contractual documents — amendments to contracts, mission letters, mobility policies — benefits from being digitised and secured. For HR teams managing multiple mobilities, Certyneo's electronic signature solution for HR enables these documents to be signed remotely, with probative value equivalent to a handwritten signature.

Contractual obligations and administrative formalities

The secondment contract: content and precautions

The secondment contract or amendment must necessarily mention, in accordance with directive 2019/1152/EU on transparent and predictable working conditions:

• the foreseeable duration of secondment;
• the currency of remuneration;
• cash or non-cash benefits related to secondment;
• conditions for repatriation;
• applicable law (generally the law of the original contract, supplemented by the mandatory core of the host country).

It is strongly recommended to add a repatriation clause specifying the terms of return in the event of illness, accident or early termination of secondment, as well as a choice of law clause under regulation (EC) No 593/2008 (Rome I).

The expatriation contract: structure and points of caution

The expatriation contract can take two forms:

1. Amendment to the existing employment contract, which suspends the original contract and specifies the conditions for return to France;
2. Local contract concluded directly with a foreign subsidiary, which then terminates the French contract (risky option as it deprives the employee of their acquired rights in France).

The first form is the most protective for the employee and the least risky for the company. It must explicitly provide for: the maintenance or otherwise of acquired benefits (seniority, classification), the conditions for reintegration at the end of expatriation, and the fate of the contract in the event of disappearance of the foreign subsidiary.

In all cases, the legal value of electronic signature on these documents is fully recognised in European law, which facilitates the conclusion of cross-border acts without physical displacement.

Compulsory administrative formalities

Beyond the contract, several formalities are mandatory:

• A1 form for secondees in EU/EEA/Switzerland: to be requested from URSSAF before departure;
• Prior notification of secondment in the host country (mandatory in all Member States since directive 2014/67/EU);
• Designation of a representative of the company in the host country (mandatory in many states, including France for foreign companies);
• Registration with local tax authorities if the duration exceeds the thresholds of the applicable agreement.

All of these documents benefit from being archived electronically and securely. The digitised payslip and archiving of contracts with time-stamping constitute evidence that can be relied on in the event of inspection by French or foreign authorities. For further information on the probative value of time-stamping of acts, Certyneo's guide to electronic time-stamping details the applicable certification levels.

Comparative summary table: secondment vs expatriation

| Criterion | Secondment | Expatriation | |---|---|---| | Duration | Limited (max. 24 months in EU) | Unlimited | | Employment contract | Maintained with originating employer | Suspended or replaced by local contract | | Social security | Original scheme maintained (A1 form) | Host country scheme | | Tax residence | Generally maintained in France | May be transferred | | Labour law | Mandatory core of host country | Full local law | | Protection of employee | High (acquired rights preserved) | Variable depending on host country | | Administrative complexity | Moderate (A1 form, prior notification) | High (local registration, CFE, agreements) |

This summary table confirms that there is no universally preferable regime: the choice must result from a case-by-case analysis taking into account the foreseeable duration, the host country, the tax profile of the employee and the company's strategic objectives. HR teams can rely on Certyneo's AI-powered contract generator to produce draft amendments compliant with the requirements of each regime, to be then validated by a specialist adviser.

Legal framework applicable to international mobilities

The management of international mobilities falls within a layering of European, international and national standards that must be mastered to avoid any risk of non-compliance.

European Union law

The regulation (EC) No 883/2004 of the European Parliament and of the Council, amended by regulation (EC) No 987/2009, forms the cornerstone of the coordination of social security systems within the EU, EEA and Switzerland. It establishes the principle of the uniqueness of applicable legislation and organises the procedures for secondment (article 12) and multi-state situations (article 13).

The directive 96/71/EC on the posting of workers, profoundly revised by directive 2018/957/EU (transposed into French law by ordinance No 2019-116 of 20 February 2019), defines the minimum rights applicable to seconded workers in the EU: remuneration, working time, accommodation conditions and the core of collective agreements.

The directive 2019/1152/EU on transparent and predictable working conditions imposes new contractual information standards, particularly for mobile workers (articles 7 to 9).

The regulation (EC) No 593/2008 known as "Rome I" governs the applicable law to contractual obligations, allowing the parties to choose the applicable law to the employment contract, subject to not depriving the employee of the mandatory provisions of the objectively applicable law.

International tax law

Bilateral tax agreements generally follow the OECD model (2017 version, updated in 2024). Article 15 of the OECD model governs the taxation of employment income. In France, Article 4 B of the General Tax Code determines tax residence, and Article 81 A of the CGI provides for an exemption from income tax for certain employees seconded abroad under strict conditions (duration of presence abroad exceeding 120 or 183 days depending on activity).

French labour law

Articles L. 1261-1 to L. 1266-1 of the Labour Code transpose the secondment directive into French law. They provide in particular for the obligation to notify in advance for foreign employers posting workers in France and the criminal and administrative sanctions applicable in the event of failure to comply (fine that may reach €500,000).

Security of acts and digital documentation

The electronic signature of international mobility contracts is governed by regulation eIDAS No 910/2014 (currently being revised under eIDAS 2.0) which confers full legal value to advanced and qualified electronic signatures. The GDPR No 2016/679 applies to the processing of personal data of employees in the context of mobility procedures, in particular for data transfers outside the EU to third countries (articles 44 to 49).

Usage scenarios: international mobilities in practice

Scenario 1 — A mid-sized industrial company managing frequent intra-European secondments

A mid-sized company in the industrial sector, with approximately 1,200 employees and subsidiaries in five EU Member States, carries out between 40 and 60 secondments of short and medium duration (3 to 18 months) per year for assembly, maintenance and technical training missions. Before digitising its processes, its HR teams managed all A1 forms, secondment amendments and prior notifications on paper, with average processing times of 12 working days per file.

By deploying an integrated electronic management and signature solution, the company reduced this timeframe to an average of 2.5 days, while reducing data entry errors by 65%. The time-stamped archiving of signed A1 forms and amendments enabled the company to respond in less than 48 hours to two consecutive labour inspection audits in different host countries, with no penalty. The ROI was achieved in less than 8 months according to the finance department's internal estimate.

Scenario 2 — A professional services group managing long-term expatriations outside the EU

A consulting and engineering group of approximately 3,500 employees sends about fifteen senior managers annually to long-term expatriation (3 to 5 years) to countries in Southeast Asia and sub-Saharan Africa, areas covered by few bilateral social security agreements. The complexity of each file — expatriation contract, amendment suspending the French contract, CFE membership, mission letter, international remuneration policy — represented on average 22 hours of administrative work per file.

The implementation of a digital platform centralising the production, signature and archiving of documents made it possible to reduce administrative burden by 40% and eliminate incidents related to unsigned or missing contract versions. The ability for employees to sign their documents from their future country of assignment, without physical return to France, was identified as a factor in improving the candidate experience for mobility.

Scenario 3 — A tech start-up in hypergrowth recruiting its first foreign employees

A French SaaS start-up, recently raised in series B, recruits for the first time three employees in the United Kingdom and Germany, while considering the temporary secondment of two French engineers to Berlin for an 8-month launch phase. The HR team, consisting of one person, has no prior experience with international mobilities.

By relying on a contract generator adapted to secondment and expatriation regimes, supplemented by an eIDAS-compliant electronic signature solution, the start-up was able to produce and have secondment amendments signed that comply with directive 2018/957/EU in less than 72 hours per file. A1 forms were obtained from URSSAF before the two engineers departed, avoiding any risk of double affiliation. The management estimated approximately €8,000 in legal fees avoided through the automation of the first levels of documentary compliance, while retaining validation by a specialist adviser for complex tax aspects.

Conclusion

Secondment and expatriation are two fundamentally distinct regimes, with profound consequences on the employment contract, social security and taxation of both the employee and the employer. Secondment provides valuable portability of social rights and contractual continuity, but imposes a limited duration and compliance with the mandatory core of the host country. Expatriation offers greater flexibility in duration, but requires a complete rebuilding of social protection and an in-depth tax analysis.

In both cases, the quality of contractual documentation — amendments, mission letters, A1 forms, prior notifications — is decisive for compliance and legal security of the mobility. Certyneo enables you to produce, have signed and archive these documents remotely, with full legal value, regardless of the location of the employee.

Discover how Certyneo secures your international mobilities or estimate your return on investment today.