Non-academic free time activities you take part in as a private person, as a rule, are not considered as work. Some activities do however require a permit for sideline activities depending on the type of your main permit.
Type 1: Researcher permit, guest researcher permit and PhD permit. Unpaid voluntary work in your free time does not require a permit for sideline activities.
Type 2: Guest PhD permit, Pay Limit permit, Positive List Permit, Trainee Permit. Several free time activities are characterized as work and will require a permit for sideline activities.
Type 1: No permit is normally required.
Type 2: A permit is required.
An organization is a group with:
Type 1: No permit is normally required.
Type 2: A permit is required.
An interest group is a group of people who meet around a common interest with:
Type 1: No permit is normally required.
Type 2: A permit is required.
Please note that these are only examples and not a complete list of types of activities that do not require a permit for sideline employment.