International workforce mobility involves a complex interplay between several national social security systems. In terms of retirement, this raises major legal questions: which legislation applies to a posted or expatriate employee? How are their acquired rights preserved from one country to another? Under what terms will their pension ultimately be settled? These are questions our International assignment services team addresses on a daily basis for executives, expatriate staff and international groups.

This coordination rests primarily on two distinct legal instruments, the interplay of which determines the full scope of a mobile worker’s pension rights: European Union law, applicable within the European Economic Area and Switzerland, and bilateral social security agreements concluded by France with non-EU States.

The European framework: coordination based on mandatory principles

Applicable legislation

Coordination of social security systems within the European Union is governed by two regulations:

• Regulation (EC) No 883/2004 of the European Parliament and of the Council of 29 April 2004 on the coordination of social security systems;
• Regulation (EC) No 987/2009 of 16 September 2009, laying down the procedure for implementing the above regulation.

These regulations are directly applicable in Member States and take precedence over conflicting national provisions — an essential point of vigilance for any company structuring an international mobility programme without taking it into account.

Four operating principles

The system rests on constant principles, established both by the texts themselves and by the case law of the Court of Justice of the European Union (CJEU):

• Principle of single applicable legislation (Article 11 of Regulation No 883/2004) — a worker may be subject to only one social security legislation at a time, in principle that of the State of employment (lex loci laboris).
• Principle of equal treatment (Article 4) — prohibition of any discrimination based on nationality in access to benefits.
• Principle of aggregation of periods (Article 6) — periods of insurance, employment or residence completed in different Member States are taken into account when establishing entitlement.
• Principle of exportability of benefits (Article 7) — cash benefits, in particular old-age pensions, may not be subject to restrictions based on place of residence.

Pension settlement procedures

Settlement rules are set out in Article 50 et seq. of Regulation No 883/2004. Each competent national institution carries out a dual calculation:

• An autonomous pension, based exclusively on periods completed in the State concerned;
• A pro-rata pension, after aggregation of periods completed across all Member States.

The insured person ultimately benefits from whichever amount is more favourable.

Illustration — An insured person who has contributed in several Member States is recognised as having a single overall career for the purpose of establishing entitlement; each State then pays a pension calculated pro rata to the periods completed on its territory, rather than a single pension split between funds.

Contributions from CJEU case law

The Court of Justice has clarified the interpretation of these principles on several occasions, notably:

• ECJ, 7 February 1991, Rönfeldt — precedence of coordination rules over less favourable national legislation;
• CJEU, 21 February 2013, Salgado González — rules on taking into account periods completed in different States;
• CJEU, 12 March 2020, Caisse d’assurance retraite — clarifications on the calculation of entitlements and coordination between institutions.

Bilateral agreements: conventional but uneven coordination

Legal basis

Outside the scope of EU law, coordination rests on bilateral international agreements, concluded on the basis of Article 55 of the French Constitution. Our International Law team regularly assists in identifying the applicable agreement and ensuring it is properly implemented.

These agreements take precedence over domestic law, in accordance with that same Article 55, subject to reciprocal application by the other contracting State.

Commonly adopted principles — and their limits

Although they vary from one agreement to another, bilateral agreements generally reproduce the following mechanisms:

• determination of the applicable legislation, often based on the principle of territoriality;
• aggregation of insurance periods;
• pro-rata calculation of pensions;
• exportability of benefits.

Their scope may nonetheless be limited: certain schemes may be excluded (supplementary or special schemes), specific conditions may apply to entitlement, or coordination may be absent for certain benefits.

Illustrations — Franco-Moroccan agreement: modelled on the European framework, it provides for the aggregation of periods and pro-rata settlement of pensions. Franco-American agreement (agreement of 2 March 1987): it coordinates the French scheme with the US Social Security system, subject to its own specific conditions, notably regarding the minimum insurance period required.

In the absence of a bilateral agreement

Where no agreement has been concluded with the State concerned, no coordination applies:

• risk of double contributions;
• no aggregation of periods;
• potential loss of pension rights.

Litigation issues and points of vigilance

Situations of international mobility give rise to significant litigation, particularly regarding the determination of applicable legislation (posting, expatriation, multiple activity), the taking into account of insurance periods, the calculation of pension entitlements, and coordination between national institutions. Our Employment Law team handles this litigation, which most often arises from a failure to plan ahead of the mobility period.

This complexity is compounded by several structural factors:

• the heterogeneity of national schemes (retirement age, required insurance period, full-rate conditions);
• the multiplicity of institutional contacts involved for a single career;
• processing delays for settlement applications, often lengthy where several funds must be coordinated.

Operational approach: securing international career paths

Legally securing international career paths requires a structured approach, both ahead of and following the period of mobility:

• Analyse the applicable status (posting, expatriation, multiple activity) with reference to Articles 11 to 16 of Regulation No 883/2004;
• Verify the existence and content of relevant bilateral agreements;
• Anticipate the settlement conditions specific to each State concerned;
• Retain supporting documents relating to periods of activity, often requested by pension funds at a late stage;
• Coordinate this process with the taxation applicable to pensions received abroad, in conjunction with our Tax team.

In summary — EU law establishes standardised, directly applicable coordination overseen by the CJEU, while bilateral agreements offer functional but legally uneven coordination. A lack of forward planning can generate significant legal and financial risks for both the company and the employee.

Frequently asked questions on retirement and international mobility

What is the principle of aggregation of insurance periods for retirement purposes?

It refers to each State taking into account periods of insurance, employment or residence completed in other EU Member States in order to determine entitlement to a pension. It is set out in Article 6 of Regulation No 883/2004.

How is my pension calculated if I have worked in several EU countries?

Each competent national institution carries out a dual calculation: an autonomous pension based solely on periods completed in that State, and a pro-rata pension after aggregation of all European periods. The more favourable amount is awarded.

What happens if there is no bilateral social security agreement with my host country?

No coordination applies: periods completed abroad are not aggregated, exposing the worker to a risk of double contributions and a potential loss of pension rights.

Does being posted abroad affect my pension rights?

No, in principle: a posted employee remains affiliated to the social security scheme of their home State, provided the conditions set out in Articles 11 to 16 of Regulation No 883/2004 or in the applicable bilateral agreement are met. Their rights therefore continue to accrue under that home scheme.

Can I receive my French pension if I live abroad?

Yes. Under the principle of exportability set out in Article 7 of Regulation No 883/2004, old-age pensions may not be subject to restrictions based on place of residence within the EU. Outside the EU, exportability depends on the provisions of the applicable bilateral agreement, where one exists.

What steps should be taken before settling a multi-country pension?

It is advisable to analyse the applicable status in light of the coordination rules, verify the existence of a relevant bilateral agreement, retain all supporting documents relating to periods of activity, and anticipate the processing timeframes specific to each national institution.

DELCADE’s role

The firm supports its clients across all these issues, in particular:

• auditing individual situations under international social security law;
• securing international mobility programmes;
• assisting with pension settlement procedures;
• managing pre-litigation and litigation matters relating to scheme coordination.

For any analysis relating to an international mobility situation or the settlement of multi-country pension rights, our International assignment services team is available to assist you.