Can cleaning staff perform their duties after the controller's other employees have finished work?

ANSWER

It is for the data controller, i.e. the employer, to decide each time during which working hours cleaning staff perform their duties. The GDPR does not prohibit some employees from performing their duties during different working hours than others in any provision. It is therefore permissible for cleaning staff to perform their duties outside the working hours of other employees. However, in the case of persons permanently employed by a given employer, it will be appropriate to provide training on the applicable personal data protection rules and on the solutions introduced by that employer (controller) relating to appropriate safeguards for processed personal data and the procedures in force at that controller.

The data controller should also obtain from cleaning staff appropriate confidentiality clauses undertaking to keep personal data confidential. Once the above requirements are met, there will be no objection to cleaning staff performing their duties outside the working hours of other employees.