Generally, a profit-making activity (being any activity pursued in the context of a contract of employment or of a regulation, or as a self-employed person) of the student is allowed as follows :

• 3rd quarter (July, August, September) : no restriction, except for the last summer vacation for the student who graduates or discontinues his studies, for the thesis student and for the young person undertaking a period of practical training in order to be appointed to a post.
• 1st, 2nd and 4th quarter : during maximum 240 hours per quarter.
  Reminder! When this standard is exceeded, the entitlement is being lost for the 3 months of the quarter.

Social allowances (sickness, invalidity, accidents at work, occupational diseases) arising from such activity are no obstacle . Voluntary activities are not considered as a profit-making activity. 

Unemployment benefits or benefits arising from a career break, are however an obstacle.