Driving in France: what are the acceptable ‘error’ margins of speed cameras?
Rumour that margins of error are set to change in 2025 has been clarified
Rules are different between fixed and mobile radars
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A rumour that the margin of error for speed cameras across France (under which a certain breach of a speed limit is tolerated) was to be increased has been making the rounds on social media.
It has led many to believe authorities would be less severe in penalising those driving caught going over the limit.
The rumour is not true as French road safety authority Sécurité Routière recently confirmed.
Despite no change to the law itself, Connexion readers may not be aware that there is a certain ‘technical margin of error’ for some speed cameras.
This “is a margin necessary to prove that, in 100% of cases, the offender was speeding, i.e. above the authorised speed limit,” the authorities say (quoted in French media Actu).
In practice, it means those flashed whilst driving ever-so-slightly above the limit are given the benefit of the doubt.
What is the margin of error?
The margin of error depends on the speed limit on the road in question.
For roads with a maximum speed of 100 km/h, the error limit is 5 km/h.
Roads with maximum speed limits of over 100 km/h have a margin of error of 5%, increasing as the speed limit on the road also goes up.
For example, drivers on a 50 km/h road will be penalised for driving at 56 km/h as this is 6 km/h over the limit, but not at 53 km/h.
However, someone driving on a road with a limit of 130 km/h will only be penalised when driving at 137 km/h or higher.
Mobile speed radars have different rules
Drivers should note that the margins above only apply to fixed speed cameras.
Mobile radars, which are becoming increasingly common in France, have their own margins of error.
Read more: More unmarked radar cars to catch speeders in France: where and how they work
Read more: How to spot an unmarked speed radar car in France
They are more generous than fixed cameras, reaching 10 km/h for roads with a maximum speed limit under 100 km/h, and 10% on roads with a maximum speed limit above 100 km/h.
In terms of crossing at a red light, drivers are only penalised after 0.1 second, to allow for a margin of error on lights changing.
Our article below details the risks for drivers who receive a speeding fine, where they can find their fines online, and how much these can reach.
Read more: 10 questions on driving fines in France
