Help looking for Frence regulations for pellet boiler installation

Hi I need some help I have had a pellet boiler installed in france by a so called specialist, I have a number of problems. We have a twin wall SS flue that doesn’t have access to sweep it , I have had three sweeps who say it can’t be swept and have additionaly said the flue is too close to wooden beams, I’m struggling to find Frence regulations that would cover this it’s making me feel very ill I suffer from Neutropenia and stress is making it worse

I’m sorry Frederick I’ve no personal experience of pellet burners but I found this which I hope is of some use to you.