In France a bureaucratic system has been introduced in the last 2 or 3 years, presumably in response to EU or bilateral regulations on double taxation. A central office our FR bank, LCL, on behalf of the FR tax office requires details of one's passport, birth certificate, UK tax regime/office, tax address & tax number. If satisfied they refrain from deducting tax at source. The bank tried to demand these details every year until I told them that they do not change very often!
Our bank manager & staff have no knowledge of - still less any competence on - Double Taxation or Avoir Fiscal.
The LCL Central Office at Montpellier provide no telephone number nor any help or advice on any question that might arise! There is a concerted attempt to minimise the burden of their services to their non-resident clients and to the French Tax Office!