On the surface this will not cost anything to the taxpayer since the cost will be borne by the carparks' owners. But this being France, my cynical side thinks

On the surface this will not cost anything to the taxpayer since the cost will be borne by the carparks' owners. But this being France, my cynical side thinks that the next step is lobbying and complaints by businesses until the government comes up with subsidies. On the other hand, that's not completely unreasonable since this new law means businesses will have to shell out hundreds of thousands of euros...