car clinic: using sat nav abroad - best laser measuring device

My family will be using satellite navigation in France this summer and as far as I know radar detectors are illegal.
Our TomTom device warns US of speed cameras.
Can we be punished for this?
GH and Otley in West Yorkshire pay close attention: France has strict driving regulations, and the story of drivers being stopped by police and fined hundreds of euros on the roadside is also unknown.
Defending the ignorance of the law is unlikely to win the sympathy of the military police.
When it comes to speed cameras, the law specifically prohibits: The French highway regulations clearly stipulate that there is anything that can actively detect speed.
Whether or not measuring equipment such as radar or laser gun is used is illegal.