Directive (EU) 2016/801 of the European Parliament and of the Council of 11 May 2016 on the conditions of entry and residence of third-country nationals for the purposes of research, studies, training, voluntary service, pupil exchange schemes or educa...

Article 23 - Teaching by researchers
‘Researchers may, in addition to research activities, teach in accordance with national law. Member States may set a maximum number of hours or of days for the activity of teaching.‘
Article 24 - Economic activities by students
‘1. Outside their study time and subject to the rules and conditions applicable to the relevant activity in the Member State concerned, students shall be entitled to be employed and may be entitled to exercise self-employed economic activity, subject to the limitations provided for in paragraph 3.
2. Where necessary, Member States shall grant students and/or employers prior authorisation in accordance with national law.
3. Each Member State shall determine the maximum number of hours per week or days or months per year allowed for such an activity, which shall not be less than 15 hours per week, or the equivalent in days or months per year. The situation of the labour market in the Member State concerned may be taken into account.‘
Article 25 - Stay for the purpose of job-searching or entrepreneurship for researchers and students
‘1. The completion of research or studies, researchers and students shall have the possibility to stay on the territory of the Member State that issued an authorisation under Article 17, on the basis of the residence permit referred to in paragraph 3 of this Article, for a period of at least nine months in order to seek employment or set up a business. [...]‘