I dont know about the Insurance implications, but you need to get an annual certificate to say that your chimney(s) have been cleaned for the Pompiers, if you have a chimney fire and they attend. We had a chimney fire when we first arrived in the Aude and the Pompier came and dealt with it very efficiently (they even swept the chimney!) but said this one was free but could charge after this if we didn`t get a certificate from a sweep.