La Cour renforce les droits des syndicats[en] 

In the Laval case (also known as the Vaxholm case), Latvian company Laval un Partneri posted several dozen workers from Latvia to building sites in Sweden. Their work included refurbishing a school in the Swedish town of Vaxholm. Swedish unions took action against Laval over the company's refusal to sign a collective agreement and to respect Swedish legislation on working conditions and minimum wages. The Swedish Labour Court referred the case to the European Court of Justice. 

In the Viking case, the International Transport Workers' Federation (ITF) and the Finnish Seamen's Union  threatened industrial action over Viking Line ’s plans to reflag one of its Finnish vessels  to Estonia and replace the crew with cheaper workers from that country. The case was referred by the Court of Appeal in London to the ECJ in November 2005. 

Presenting his conclusions on the Laval case on 23 May, Advocate-General Paolo Mengozzi argued that "where a member state has no system for declaring collective agreements to be of universal application", the Posting of Workers Directive "must be interpreted as not preventing trade unions from attempting, by means of collective action (...), to compel a service provider of another member state to subscribe to the rate of pay determined in accordance with a collective agreement which is applicable in practice to domestic undertakings in the same sector". 

In the Viking case, Advocate-General Miguel Poiares Maduro expressed the view that trade unions could take collective action to dissuade a company from relocating within the community, as long as this did not partition the labour market along national lines or prevent a relocated company from providing services in another member state. 

He argued: "Article 43 EC does not preclude a trade union or an association of trade unions from taking collective action which has the effect of restricting the right of establishment of an undertaking that intends to relocate to another member state, in order to protect the workers of that undertaking. It is for the national court to determine whether such action is lawful in the light of the applicable domestic rules regarding the exercise of the right to collective action, provided that cases of intra-Community relocation are not treated less favourably than cases of relocation within the national borders."

ITF General Secretary David Cockroft said: "This is an interesting opinion for anyone studying the case. There are favourable and unfavourable elements. We welcome Senor Maduro's championing of unions' right to collective action, but believe that there is cause for re-evaluation of that part of the opinion that might encourage businesses to believe they can override those rights through a kind of cross-border hopscotch."

John Monks, General Secretary of ETUC, the European Trade Union Confederation, said: "This is good news for unions and for Europe. Union rights to take action to compel a company from another member state to observe collective agreements have been upheld. The advocates-general have also upheld trade union action to dissuade a company from relocating to another country. We will study the details carefully but these are important landmark and positive opinions for all European trade unions and for Europe."

Party of European Socialists  President Poul Nyrup Rasmussen  said: "This is excellent news. It removes the sword hanging over European collective bargaining and offers the chance of a decent deal to women and men who travel to another country for work. It shows that the EU is not about a race to the lowest wages and worst working conditions – it is about giving rights to workers wherever they earn a living within the European Union. I am relieved that the Court has ruled in favour of working people."