Mandatory signs
Round blue signs impose an obligation: direction, reserved lane, equipment.
Updated 13 June 2026
Mandatory signs: the blue that commands
Mandatory signs are round and blue with a white symbol in the centre. They impose a specific behaviour: follow a direction, use a reserved lane, or wear specific equipment. Unlike prohibition signs that say 'do not', mandatory signs say 'do this'.
Round + blue background = mandatory. The driver must absolutely comply with what the sign requires.
When does the obligation start and end?
As with prohibitions, the obligation takes effect at the sign. It ends either at the next junction or when an end-of-obligation sign appears. End-of-obligation signs are identical to mandatory signs but crossed by a red line.
Compulsory directions
Compulsory direction signs feature one or more white arrows on a blue background. They require you to follow the direction indicated. You have no choice to go elsewhere.
Reserved lanes and equipment
Some mandatory signs designate lanes reserved for a particular category of user. Buses, cyclists or pedestrians may have lanes exclusively for their use. Other signs require the use of equipment, such as snow chains in the mountains.
Snow chains are only compulsory on snowy or icy roads. On dry road surfaces, it is forbidden to drive with chains as they damage the road and reduce grip.
Since the Mountain Law, certain areas require you to carry winter equipment (chains or winter tyres) from 1 November to 31 March, even if the road is not snowy at the time you pass through.
More obligations
Recap
- Round blue = mandatory (direction, reserved lane, equipment).
- The obligation ends at the next junction or at the end sign (crossed with red).
- Round blue bicycle sign = compulsory lane. Square blue bicycle sign = recommended lane.
Test yourself
A round blue sign with a white symbol is a sign of:
- ○Information
- ○Prohibition
- ✓Obligation
- ○Danger
Correct answer : Obligation
What does an end-of-obligation sign look like?
- ✓Identical to the mandatory sign but crossed by a red line
- ○White background crossed by a black line
- ○Red background crossed by a white line
- ○Identical to the mandatory sign but in grey
Correct answer : Identical to the mandatory sign but crossed by a red line
Sources: Sécurité routière (securite-routiere.gouv.fr) and service-public.fr.