In other words: can the employer rely on an objective justification?

In a recent judgment, the Subdistrict Court in Rotterdam considered a case in which an employee undertook external activities while on sick leave, despite her employment contract containing a prohibition on such activities. The employer sought to enforce this prohibition—but would that position be upheld by the court?

The case in brief

The case involved an employee who reported sick to her employer. However, during her period of illness, she gave a presentation at a business event without informing her employer in advance. The employment contract included a clause prohibiting external activities unless the employer had granted prior written consent. The clause also provided for a contractual penalty of one gross monthly salary in the event of a breach.

The employer withheld this penalty from the employee’s final settlement, arguing that she had breached the clause. The employer further alleged that the employee had not actually been unfit for work but was working for her own business. Additionally, the employer maintained that delivering a presentation while on sick leave could hinder the employee’s recovery.

The Court’s Reasoning

The Subdistrict Court did not accept the employer’s arguments. It held that reliance on a external activities clause requires an objective justification, as set out in Article 7:653a of the Dutch Civil Code. Such justification need not be included in the clause itself but must be provided at the point at which the employer invokes the clause.

The mere fact that an employee who is signed off sick speaks at an event is insufficient. Furthermore, the employer’s assertion that the employee was not ill contradicted its alternative argument that the employee’s recovery was impeded—if the employee was not ill, there could be no question of recovery. The court held that the employer had failed to sufficiently substantiate why this employee should not have been allowed to carry out external activities.

In the absence of an objective justification, the court ruled that the clause external activities was void. Accordingly, the penalty should not have been deducted from the employee’s salary.

Read the full judgment here.

Implications for Practice

Employers who wish to restrict employees from engaging in work outside regular working hours must be aware that, under Article 7:653a of the Dutch Civil Code, they must provide a legitimate justification for such restrictions. In practice, this means:

• A standard clause prohibiting secondary employment may not be sufficient.
• There must be a specific and objectively justified reason for withholding consent, such as concerns relating to safety, health, competition, or confidentiality.
• Even during sick leave, consent may only be refused if it can be demonstrated that the secondary activity impedes recovery or otherwise adversely affects legitimate interests.
• Contradictory assertions—such as claiming an employee is not ill, while also claiming their actions hinder recovery—undermine the credibility of the employer’s reliance on the clause.
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Conclusion

This judgment underscores the need for employers to exercise caution when invoking a external activities clause, particularly in the context of sick leave. The mere fact that an employee is off sick but still undertakes certain activities does not automatically amount to a valid ground for enforcement. The justification must be objectively linked to legitimate interests, such as health, recovery, or operational needs.

For employers, the challenge lies in developing and applying a well-reasoned and substantiated policy. For employees, this ruling offers reassurance: secondary work is in principle permitted, unless the employer can objectively justify restrictions.

Do you have questions about drafting, enforcing, or assessing a secondary employment clause? The employment law specialists at SPEE advocaten & mediation are pleased to assist you.