Yvelines postal codes — Ile-de-France, France

Yvelines (département 78) is one of the départements of the Ile-de-France région. Its towns include Mantes-la-Jolie, Rambouillet, Saint-Germain-en-Laye and Versailles, each surrounded by the communes whose postal codes are listed above.

Administrative structure

France is organised into three administrative levels: the région, the département, and the commune. Yvelines is a département within the Ile-de-France région, and is itself divided into communes — the towns and villages whose postal codes are listed above.

How postal codes work in Yvelines

French postal codes are five digits long, written as a single block with no space (for example, 78660). The code reads from left to right, moving from the département down to the local delivery area.

The first two digits identify the département, so every postal code in Yvelines begins with 78.

The remaining three digits narrow the code down within the département. They identify the delivering post office or commune, and in larger towns a specific delivery zone; they do not reproduce the commune's official INSEE code, even where the two look similar.

Some codes are reserved for CEDEX (Courrier d'Entreprise à Distribution EXceptionnelle) service. A CEDEX code is assigned to a business, administration, or other recipient that receives high volumes of mail, and it routes post through a dedicated handling arrangement rather than a standard geographic round. CEDEX appears after the town name in the address, sometimes with a number identifying the specific account.

Addressing format

A correctly formatted address in Yvelines places the postal code before the town name, on the same line, with the town name in capital letters. For example:

Recipient name
Street and number
78660 ABLIS

The postal code and town share the final line, postal code first, town in uppercase. A CEDEX designation, where it applies, is added after the town name.