The discussions are under way to restrict circulation of diesel powered vehicles in Paris starting next year 2015. They are looking to introduce charges imposed at the entry Portes to vehicles entering the city, as in London. These will be set at levels to encourage the use of lower pollution vehicles. They are continuing to improve the public transport options but recognise they cannot completely replace the use of private vehicles.
If you are touring France, you might want to think of doing Paris first and then going to the airport to pick up your car for seeing the country.