Employers particularly appreciate it when they can deploy their employees flexibly. This is also recognised by the legislator. According to Section 12 of the Part-Time and Fixed-Term Employment Act (Teilzeit und Befristungsgesetz), it is possible to agree work on call with an employee, meaning that the work can be performed according to the workload as instructed by the employer. However, extreme caution is required when agreeing such on-call work:
The agreement must contain a specific duration of weekly and daily working hours. If the duration of the weekly working time is not specified, a working time of 20 hours is deemed to have been agreed. If the duration of the daily working time is not specified, the employer must utilise the work performance for at least 3 consecutive hours. If, in addition, a minimum or maximum working time is agreed for the duration of the weekly working time, the employer may only call up to 25% of the weekly working time in addition or only up to 20% of the weekly working time less. It is therefore customary and advisable to agree on so-called time corridors for on-call work, within which the call-off takes place.
Accordingly, the Federal Labour Court ruled on 18 October 2023 — 5 AZR 22/23 that an employer must pay 20 hours per week, even though the employee had worked fewer hours in accordance with the statutory regulation. A deviating interpretation of the agreed working hours could only be considered in absolutely exceptional cases — the employer would therefore have to explain and prove why the working hours should exceptionally be less.
The use of this flexibilisation instrument can therefore lead to unpleasant consequential costs if these statutory provisions are disregarded in the corresponding agreement.