They mainly use super fast cars to warn those baddy, "Dun try,
your car still not good enough"
Also, the Lamborghini is only for France police to transport organs
like hearts for organ transplant from one place to another. And of
course, like what has already been stated by others before me,
police drive it to give presentations at schools or etc.
For catching speeders, police use second-grade cars. Like recently
the France police imported many Subaru.