A new line numbering system
Why does the number of the lines change?
The bus network in Île-de-France is made up of nearly 1,900 lines and the current numbering system means that there are many lines with the same number. The timetable and route search tools are regional. It is therefore often complicated to find the line you are interested in. For example, there are 13 bus lines that have the number 10!
How to find your way around the new issues?
Île-de-France has been divided into departments and sectors.
- In the Mantois catchment area, all your lines are now renamed from the "54" call sign , to which a number is added to be consistent, where possible, with the old name of the line (e.g.: line 74 becomes line 5474).
- Express line numbers start with the number of their department (e.g. line 7820, former A14 Mantes line).
What will this new number bring to users?
You will find your bus line more easily because it will be the only one in Île-de-France to have this number! Thus, when you type his number in the search engines of the application or the iledefrance-mobilites.fr site, you will directly access the information about this line.
An evolution of the offer in your territory
From 1 September 2025, several lines are evolving to offer:
- Better service to strategic areas (city centre, shopping centres, etc.)
- More frequency in the evenings and on weekends
- More direct routes to schools
Some lines are postponed:
- The G is transferred to lines 5406 (former line K) and 5408 (former line X) to offer an extended transport solution during rush hour and on Sundays
- Line 21 is moved to line 5482 (former line 52) for more direct trips to the C. Claudel high school in Mantes-la-Ville
Practical information
A question, a request for information about your lines?
Application Île-de-France Mobilités
Site: iledefrance-mobilites.fr > Getting around
Phone : 0800 10 20 20
Our agents will be available all summer long on your lines.
Find our complete flyer by clicking here.
Soon find all your back-to-school schedules.
We wish you a great summer on your lines!