Yes but it was long ago and people forgot. But yes, French citizens are paying for the autoroutes twice: built with public money and then again with tolls to use them.
Presumably the privatisation process involved the transfer of cash from the companies buying them to the government, and hopefully that was more than the cost of construction.
There's maintenence in local roads too. And maintence is broadly relative to the damage caused, which is relative to the 4th power of axel weight. A 30 ton truck will cause thousands of times the damage of a 2 ton car, but doesn't pay thousands of times the price.