Ancillary activity

Duty of fidelity

When an employee performs a secondary activity, he/she is still bound by his/her duty of fidelity to his/her main employer, in accordance with Article 321a of the Code of Obligations (CO). The employee must not compete with his main employer and must give his all to perform his work.

During working time

During working time, the employee is obviously not allowed to perform any paid activity for a third party. Moreover, an employee who performs an activity for a third party during an alleged incapacity to work is in serious breach of his duty of loyalty.

Maximum working week

The maximum working week is 45 hours for workers in industrial enterprises and office staff and 50 hours for all other workers.

Daily rest

Article 15a LTr provides that the worker must have a daily rest period of at least 11 consecutive hours following the daily work. The ancillary activity must not interfere with the daily rest period.

Frontier workers

If a frontier worker carries out a secondary activity at a rate of 25% or more in his country of residence, he will be subject to the social security system of that country.

Internship for foreign students

Foreign students must in principle apply for a work permit in order to carry out an internship in Switzerland. This application is facilitated if the internship is carried out as a sideline to the studies.


The employer must regulate the incidental activity and its many facets. If these rules are violated, the employee may be punished by a warning, ordinary dismissal or, in serious cases, immediate dismissal.

Work for a third party

The duty of loyalty requires that the employee devote his or her working hours entirely to the service of the employer. The employee may not perform paid work for a third party during his working hours. This is also the case if the employee is unable to work. An employee who is unable to work must use his absence to regain his full working capacity. If the employee works for a third party during this period, he is in serious breach of his duty of loyalty in that he delays or prevents his recovery. The violation is all the more serious when the activity carried out is in competition with that of the employer.

Top Articles