First, it sought to give the public a better understanding of the FCC, a proposed particle accelerator (a machine that accelerates subatomic particles to near light speed before smashing them together to reveal their structure) that would succeed the present Large Hadron Collider. Second, it allowed CERN to better understand the views of local communities on both sides of the French-Swiss border.

CERN framed the approach as a way to give everyone the information needed to develop an informed opinion on the project, whether favourable, unfavourable or undecided. For the laboratory, the interactions provided an important opportunity to listen to people and better grasp the questions, expectations and concerns of those living near the potential site.

What happens next?

The results of both the French and Swiss exercises will be published in early December 2026. CERN will then endeavour to issue a formal response by the beginning of March 2027, setting out in particular the follow-up actions that will form the basis of future dialogue with local communities and authorities.

After that step, CERN will enter a phase of continuous consultation with local communities in the lead-up to a decision by the CERN Council, the body made up of representatives of all Member States, expected in 2028 at the earliest.

Approval from the Council would not constitute an actual authorisation to build the collider, nor would it signal the end of the dialogue. The project would remain subject to French and Swiss procedures and authorisations, and CERN has indicated that another public consultation process might be organised for the next stages of the project.

Members of the CERN community will have their own chance to hear initial feedback on 12 November 2026, at an update session running from 1.00 pm to 2.00 pm in the Georges Charpak Room (Room F, building 60/6-015).

For now, the questions and concerns of two countries rest with the results due in December.