The regulations for mounting fire extinguishers and smoke detectors differ in each country. In Germany (read here) some federal states explicitly require that smoke detectors are fitted in apartments and houses. It is very easy to find such information on the internet. (Generally it is an additional safety precaution if you have a fire extinguishers in the apartment.) You should ensure that you have a TV license and adhere to the general rental terms. Here there are also different regulations in the various countries (and possibly federal states.