The GSC offers around 100 paid traineeships a year to EU nationals who have completed at least the first part of their university studies, and have obtained a degree certificate. Traineeships are split into two different periods, each lasting five months:

• 1 February to 30 June,
• 1 September to 31 January.

The GSC offers around 20 unpaid traineeships per year. These traineeships are for 3rd, 4th or 5th year university students who have to do a compulsory training period as part of their course. Traineeships are split into two different periods, each lasting from 1 to 5 months:

• 1 February to 30 June,
• 1 September to 31 January.

More:

http://www.consilium.europa.eu/council/traineeships-at-the-gsc?tab=General-information&lang=en