Résumé : This PhD presents a compendium of six publications dealing with the process of Europeanisation of democracy at work, and within that overarching framework, the process of Europeanisation of worker representation on corporate boards of directors.The Europeanisation of codetermination rights at enterprise level is analysed from an institutional and socio-political perspective, interested in actors and institutions, and addressing codetermination as an area of EU social policy and EU trade union strategy. The publications are presented in three parts. One contextualises the research and the historical and legislative developments that have led codetermination to become a rather limited area of EU social policy under the shadow of the German model and actoral strategies, although significantly eroded by the effects of EU integration and corporate mobility. The second part addresses the process of top-down Europeanisation of worker representation on boards. It examines the implementation of the European Company (SE) Directive 2001/86 and how clauses of participation have been negotiated in SE agreements, generally weakening previous national models, as well as critically analyses the legal and political implications of the CJEU Case Erzberger, which constituted a sort of impasse for the development of Europeanisation of worker representation on boards in multinationals governed by national law. A final third part examines the process of bottom-up Europeanisation of these rights, according to national law and practice and independently of any EU regulation. The findings question the idea of a Europeanisation by stealth and tending to a Euro-democratic process. Without a proactive legal and political action from institutions and social actors at EU level, particularly trade unions, codetermination rights may lose from their democratic legitimacy component.