Paris is divided into 20 districts/neighbourhoods called arrondissements.
THE 20 ARRONDISSEMENTS OF PARIS
Beginning at the centre of the city, with the 1st, then spiralling out in a clockwise direction to the 20th. Each of these districts has its own attractions and character. For your holiday in Paris you really don't need to know the arrondissements but it is a good way to divide up the city into manageable tourist destinations and attractions.
Parisians refer to them by their numbers, ie those living in the 6th district as 6ème (or 6e).Paris postal codes are all 750.. with last two digits being the arrondissement number, ie 75018 is the 18th district.
When considering where you want to be located within the city it's about choosing the right district or neighbourhood and hotel / apartment to suit your requirements and budget, although, anywhere within the city boundaries will give you easy access to its delights due its modern and efficient (most of the time) transport system.
From a tourist point of view you'll probably know the areas of Paris better by their more popular names such as 'The Latin Quarter','Montmartre','The Marais', 'St. Germain-des-Pres' etc and have left home with images of these in your head. These names do not have the same geographical boundaries but instead are perhaps more defined by unique characteristics and cultural differences.