SAF is an undertaking which supplies fuel to several airports in Finland. Its employees fuel aircraft and conduct quality controls and other auxiliary tasks in relation to the aircraft in those airports. In accordance with a contract concluded in 2010, SAF was required to use temporary agency workers to replace permanent workers on sick leave or to deal with peaks of work. Before 2010, SAF used the services of another temporary-work agency for the same purposes.

AKT brought an action before the Finland Employment Tribunal seeking an order that Öljytuote and SAF pay a financial penalty in accordance with Article 7 of the Law on collective agreements for having contravened Paragraph 29(1) of the applicable collective agreement. AKT submits