Case law Developments in PIL

Nuclear Plants, Posting of Workers and Mutual Trust

Curia-1The author of this post is Vincent Richard, Senior Fellow at the Max Planck Institute Luxembourg for International, European and Regulatory Procedural Law.

On 14 May 2020, the CJEU gave a preliminary ruling in Bouygues travaux publics, a case regarding the binding effect of social security certificates issued by the social security authority of a Member State on the courts of another Member State where workers are posted. The judgment was rendered in the context of French criminal proceedings against Bouygues travaux publics for infringements of labour law during the construction of the EPR nuclear power plant in Normandy.


EPR nuclear reactors represent the new generation of nuclear power plants conceived to be safer than current reactors. Construction have started in Finland and France fifteen years ago but both projects ran into costly delays. So far, two reactors have been completed in Taishan, in the Guangdong province of China while the European nuclear plants are still under construction.

The EPR nuclear plants constructed in Olkiluoto in Finland is scheduled for 2021 after a dispute that was concluded with a settlement whereby the Areva-Siemens consortium agreed to pay 450 million euros to the Finnish utility company TVO. Two more reactors are being built at Hinkley Point in England with a starting date scheduled between 2025 and 2027.

EPR FlamanvilleConstruction of the French EPR reactor started in 2007 in Flamanville in Normandy with a projected cost of 3.3 billion euros. According to French newspapers, completion is now expected for 2023 with a total cost of more than 12 billion euros. The project has faced technical difficulties but it has also run into legal troubles surrounding employment contracts of Eastern European workers.

Criminal Proceedings in France

To complete such a massive project, Bouygues travaux publics formed a limited partnership with two other undertakings and it subcontracted the contract to an economic interest grouping that included, among others, Welbond, a company domiciliated in France. This grouping itself used subcontractors, including Elco, a company established in Romania to supply Romanian workers and Atlanco Ltd, a temporary employment company established in Ireland with a subsidiary in Cyprus and an office in Poland to supply Polish workers.

An investigation by the French nuclear safety authority and then the French police revealed that, between 2008 and 2012, there had been more than one hundred unreported workplace accidents on the construction site, as well as several other infringements of French labour law. Subsequently, Polish workers sued the above-mentioned companies before the labour court of Cherbourg, France, and French prosecutors initiated criminal proceedings against Bouygues, Welbond and their subcontractors before the criminal court in Cherbourg (all decisions in French can be found here).

On appeal, the court of appeal of Caen held that the companies were guilty of the offences of concealed employment and unlawful provision of workers. It ruled that Elco, the Romanian company, could not rely on the European legislation on posting of workers because it had a stable and continuous activity in France. Therefore, the contracts should be characterised as French employment contracts and the company should have complied with French labour law and declared the workers to French authorities prior to their recruitment. Workers were hired in Romania for the sole purpose of working in France and some of them had worked there for more than 24 months. Similarly, Atlanco had hired temporary Polish workers to work in France through its Cypriot branch by making them sign a contract drawn up in Greek. Atlanco never appeared in court but Bouygues and Welbond were held guilty of concealed employment offences for the workers supplied by Atlanco, by not declaring the workers to French authorities. This “declaration prior to recruitment of employees” aims to register workers officially so that the offence of concealed employment be easier to prove in the absence of such declaration.

Question Referred to the CJEU

The main argument of the defendants was to rely on the legal value of the E101 and A1 certificates that they had provided to French authorities. These certificates were required by regulations n. 1408/71 and 574/72 (replaced respectively by regulations n. 883/2004 and 987/2009) on the coordination of social security systems. These forms, issued by the social security authority of the Member State of origin, certify that the worker is covered by the social security of that Member State and thus exclude the application of another social security legislation.

According to CJEU case law in Herbosch Kiere and A-Rosa Flussschiff GmbH, the certificates are binding on both the social security institutions and on the courts of the Member State where the work is carried out. If the authority of this Member State raises doubts as to the correctness of the certificate, the issuing authority in the Member State of origin must re-examine the grounds on which the certificate was issued (Fitzwilliam). In Altun, the CJEU provided for a limited exception whereby a court can disregard the certificate when evidence supports the conclusion that a certificate was obtained fraudulently and only if the issuing authority fails to take that evidence into consideration for the purpose of reviewing the certificate.

In the present case, French lower courts have applied French labour law, whereby employers have to make a declaration to social security authorities prior to recruiting employees. This declaration allows to complete several administrative formalities at once. It aims to register workers officially not only to the social security scheme but also to the occupational health services or retirement schemes. Before the Cour de cassation (which is the French Supreme Court for civil and criminal disputes) the defendants argued that this declaration was not necessary because French authorities were bound by the foreign certificates, and therefore French social security and labour laws do not apply. Unsure about the scope of these certificates, the French Supreme Court asked the CJEU whether the binding effect of the certificates regarding the affiliation to social security extends to the law applicable to the labour obligations of the employer, such as the French declaration prior to recruitment. For the CJEU, the question is tantamount to deciding whether the certificate binds the court of the Member State where employees are working not only in the area of social security, but also in the area of employment law.


In its decision, the CJEU stresses that the certificates are designed to facilitate freedom of movement for workers and that Member States should apply the principle of sincere cooperation, laid down in Article 4(3) TEU, which also entails the principle of mutual trust. Consequently, the certificates create a presumption that workers are properly affiliated to the social security scheme of the issuing Member State and this declaration is binding on the Member State where the work is carried out. However, because the certificates are prescribed by the European regulations on the coordination of social security systems, their scope is limited to social security matters, and they do not have a binding effect in employment law matters.

The Court held:

Article 11(1)(a), Article 12a(2)(a) and (4)(a) of Council Regulation (EEC) No 574/72 of 21 March 1972 laying down the procedure for implementing Regulation (EEC) No 1408/71 on the application of social security schemes to employed persons, to self-employed persons and to their families moving within the Community, in the version amended and updated by Council Regulation (EC) No 118/97 of 2 December 1996, as amended by Regulation (EC) No 647/2005 of the European Parliament and of the Council of 13 April 2005 and Article 19(2) of Regulation (EC) No 987/2009 of the European Parliament and of the Council of 16 September 2009 laying down the procedure for implementing Regulation (EC) No 883/2004 on the coordination of social security systems, must be interpreted as meaning that an E 101 Certificate, issued by the competent institution of a Member State, under Article 14(1)(a) or Article 14(2)(b) of Council Regulation (EEC) No 1408/71 of 14 June 1971 on the application of social security schemes to employed persons, to self-employed persons and to their families moving within the Community, in the version amended and updated by Regulation No 118/97, as amended by Council Regulation (EC) No 1606/98 of 29 June 1998, to workers employed in the territory of another Member State, and an A 1 Certificate, issued by that institution, under Article 12(1) or Article 13(1) of Regulation (EC) No 883/2004 of the European Parliament and of the Council of 29 April 2004 on the coordination of social security systems, as amended by Regulation (EC) No 465/2012 of the European Parliament and of the Council of 22 May 2012, to such workers, are binding on the courts or tribunals of the latter Member State solely in the area of social security.


This decision is not ground-breaking but it will help the French authorities in their fight against social dumping. If the French Supreme Court considers that the effect of the declaration prior to recruitment are broader than social security legislation, French prosecutors will be able to sue employers before criminal courts for offences of concealed employment if companies do not submit this declaration to French authorities. That being said, in the EPR case, the court of appeal ordered defendants to pay fines ranging from 15.000 to 60.000 euros while the loss to French social security is estimated by French newspapers to be between 10 and 12 million euros.

Overall, the reasoning of the CJEU in this case and in Altun will be familiar to specialists of the Area of Freedom, Security and Justice. Here, the principle of mutual trust is derived from the principle of sincere cooperation enshrined in Art. 4(3) TEU rather than from the principle of mutual recognition of judgments of Art.67(3) TFUE but its function as an interpretative imperative is the same. Similarly, the CJEU accepted in Altun that mutual trust is not without limit and that there may be exceptional circumstances in which a court is allowed to disregard a legal document issued in another Member State.

%d bloggers like this: