Translated from Dutch NOS TV today:
The protest was against the French support for the nuclear power plants. The Doel and Tihange power plants, both close to the Dutch border, are owned by the French state for more than 25%.
Especially the Tihange 2 and Doel 3 power stations regularly have problems with cracks and other problems. The campaigners called on the president to shut down the power stations for ever.
During the award ceremony, the protesters made noise and shouted slogans.