The pupils gathered at 8am at their schools and marched towards the city centre, temporarily blocking traffic on certain roads as they went. Police said there had been no requests for permission, either for the march or the rally in the town centre.
Marc Heeb, director of the Bern police, expressed astonishment that the pupils had not applied for the proper permission, and said the police would "keep an eye on" the protest.
A similar anti-nuclear demonstration was held by school pupils in the city's Bundesplatz square at the beginning of April, but two of them - and a parent – had requested and received the proper permission.
The event organizers told the Capital FM radio station that they are not expecting the participants to be punished, but said that if the police executed any "repressive measures," they would re-think their strategy.
The pupils said the purpose of the protest was to get the Swiss government to change its energy policy. They want an alternative to the "short-term, profit-orientated society."
They added they were holding the strike because their futures were decided by powers beyond their control, so there was no point going to school.