The article analyses the CJEU ruling C-311/21 TimePartner, where the Court interpreted the option provided in the Temporary Agency Work Directive for social partners to derogate from the principle of equal treatment. The CJEU concluded that the term ‘while respecting the overall protection of temporary agency workers’ is a criterion for using the option to derogate, and that a derogating collective agreement must be subject to legal review of fulfilling this criterion, even in Member States where collective agreements are presumed to be correct. Furthermore, the CJEU ruled that in order to respect the overall protection, any disadvantages in basic working conditions, i.e., working time and pay, should be set off against other advantages relating to the basic working conditions for the temporary agency workers. Finally, that the assessment is an in concreto comparison of disadvantages and advantages in terms of the basic working conditions applicable at the specific user undertaking. The article argues that the CJEU, with this approach, at the same time restricts the room for negotiation of national social partners concluding derogating agreements, and directs the legal review of the national judiciaries. This approach may interfere in the national industrial relations systems in some Member States more than others. The article then discusses how the Danish legal framework respects the overall protection of temporary agency workers. Temporary agency workers are addressed in many collective agreements in force at user undertakings with a view to counteracting circumvention of the collective agreement, and likewise, many temporary work agencies are covered by collective agreements. The transposition process in 2013 of the option to derogate is presented. The Danish Supreme Court in 2019 ruled, that the term ‘respecting the overall protection’ in the derogation provision in the Danish Temporary Agency Workers Act constitutes a legal criterion, which can be subject to judicial review, and is not an automatic consequence of a collective agreement. The article discusses how an assessment of the level of protection would be carried out in Danish industrial judiciaries, taking inspiration from earlier industrial case law comparing the overall protection of competing collective agreements. The article finally asserts that the approach of the CJEU in the TimePartner ruling protects temporary agency workers rather than pursuing flexibility in the labour markets, and as such favours one of the dual aims of the Directive. In that light, the approach taken by the CJEU ensures that derogating collective agreements meet certain standards in terms of the basic working conditions of temporary agency workers. At the same time, the ruling does not interfere with other negotiated or legislated working conditions, where the TAW Directive does not in itself require equal treatment or ‘overall protection’. The limitation of the TAW Directive to concern equal treatment only for basic working conditions, and not all working conditions, thus continues to allow a degree of flexibility for employers as well as for temporary agency workers.