Zef has been a lawyer since 1998. He is co-founder and partner of SteensmaEven.
Zef works in all important areas of labour law. He has a focus on European and collective labour law (collective labour agreements / collective dismissal / employee participation). He has extensive experience with reorganisations, corporate governance and the transfer of undertaking.
Zef is a professor of European Labour Law at Erasmus University Rotterdam. In his inaugural speech in 2018, he discussed the potential tension between the economic opportunities that European law offers companies and employees and the social protection that national labour law seeks to provide. He received his PhD in 2008 in the field of cross-border collective labour agreements in Europe.
In addition to his academic education, Zef also teaches postgraduate courses at the Grotius Academy and PALA, among others. He regularly gives lectures on various employment law topics, inside and outside the Netherlands.
Zef is the editor-in-chief of the international magazine European Employment Law Cases. He is the editor of the ‘Tijdschrift Arbeidsrecht in Context’.
Zef regularly publishes in employment journals and books. Among other things, he is co-author of the authoritative handbook ‘Arbeidsrechtelijke Themata’. Zef contributes to the interpretation of labour law for the future through his contribution to the Code of Work 2025. He was a national expert in the European report “Cross-border Collective Actions in Europe: A Legal Challenge” and participated in the evaluation of the Act on Combating Sham Arrangements (‘Wet Aanpak Schijnconstructies’) by writing an expert report for the Ministry of Social Affairs and Employment.
Zef is a board member of the Dutch Employment Lawyers Association, a member of the Rotterdam Employment Lawyers Association and the European Employment Lawyers Association.