Traffic offence - 3rd degree

I received a letter from Police this morning about a traffic offence in the Schuman area - "non respect de la ligne jaune continue". These are temporary lines whilst works are going on around the tunnel area, but yes I know they should be treated as regular lines. I've no recollection of crossing over any yellow line but am not going to contest it.

Part of the fine states "+ selon RN particuliere non titulaire d'un permis de conduire". What does RN stand for? I have a full driver's licence, so this is a concern.

The letter gives no indication of how much the fine will be. Will there be a court appearance? I hope not. Many thanks for any advice.