Richard Harbus for The New York Times

The City of Light could soon become the city without S.U.V.’s.

Government officials in Paris are considering putting in effect a series of regulations that would heavily tax, or completely ban, S.U.V.’s and high-polluting, old diesel vehicles from entering the city center.

Details of the proposed plan — the hours during which charges would apply, the fee amount and the charge-zone boundaries, for starters — are still being determined.

Many modern S.U.V.’s are built with the same engines and transmissions found in sedans and crossover vehicles. A car technically classified a subcompact but fitted with a high-horsepower gasoline engine could be allowed a free pass, despite polluting more than a cleaner-running but larger S.U.V. Therefore, a blanket ban seems unlikely. The objective of any proposed legislation seems primarily intended to alleviate urban congestion, no matter the type of vehicle.

Such unknows nevertheless have not stopped French politicians from taking aim. “I’m sorry, but having a sport utility vehicle in a city makes no sense,” said Denis Baupin, deputy mayor of Paris, in an interview with RTL radio from December. “Sell it and buy a vehicle that’s compatible with city life,” Mr. Baupin advised owners of high-polluting vehicles. This could include old diesels, whose carbon emissions were notoriously higher before more stringent emissions standards took effect.

“‘Old diesel’ is really hard to define,” says François Roudier, vice president of communications for the Paris-based Comité des Constructeurs Français. While the C.C.F.A. is not directly associated with laying groundwork for Paris’ proposal, Mr. Roudier says such programs are inherently complicated and politically charged. A ban on older diesels, for example, could be construed as being unfair to people unable to afford a new vehicle.

For their part, French car manufacturers appear ready to discuss the proposal — though many admit the details remain too undefined for specific comment. “First discussions will begin at the end of this month between carmakers and French authorities,” said Raphaelle Gomez, a spokeswoman for Renault, in an e-mail. “It is too early now for a stance of Renault on that topic.”

Unlike in the United States, S.U.V.’s have never played a vital sales role in the lineup of French manufacturers. “We are not really a major player in that market,” explains Anouk van Vliet, spokeswoman for Citroën. Throughout 2011 and 2012, Citroën and its partner brand, Peugeot, will introduce a new diesel-hybrid drivetrain. The Peugeot 3008 hybrid crossover, on sale in Europe later this year, might cut a small S.U.V.’s profile, but its estimated 62-miles-per-gallon efficiency would shame most economy cars.

Not surprisingly, support for the proposal is strongest with companies specializing in electric power. Gildo Pastor, chief executive of Monaco-based Venturi Automobiles, refers to the proposal as “the ideal condition for the fast deployment of E.V. in France.” Venturi presently builds electric-powered delivery vans for the French postal service, though the company is best known for its $390,000 electric-powered sports car, the Fetish.

Other French cities, including Grenoble, Lyon and Aix-en-Provence are prepared to follow Paris’ lead to reduce traffic and pollution through some form of congestion charge. Similar systems have been enacted in London, Singapore and Berlin, with varying fees and restrictions based on vehicle and driving time. New York Mayor Michael R. Bloomberg considered a similar charge plan to make the city more environmentally friendly, but the plan proved highly contentious and was not enacted.