Why in this day and age, do Britain and France still refuse to arm their police?
Most French police are armed. These may have been the Police Municipale who are basically little more than traffic and parking enforcement. The Police Nationale are responsible for criminal enforcement in the big cities, with the Gendarmerie responsible for smaller towns and the countryside. Nationales are armed with the SIG Sauer SP2022 and, as needed, with the the SIG SG -540 assault rifle.