Paris, Lyon, Grenoble and Aix-en-Provence are among the cities planning to try restrictions on gas-guzzlers in late 2011 or 2012.
The Environment Ministry says officials in each city are still discussing precisely how the restrictions would work -- what types of cars would be affected, in what neighborhoods, during what hours or periods of the year. Exact penalties are also an open question.
Many other European cities, including London and Berlin, already have "low emission zones," with varying restrictions on the type of vehicles targeted.
