FRANKFURT, Germany—The latest models of Mercedes cars cannot be sold in France because they still use an air conditioning refrigerant that the EU says emits excessive greenhouse gases and should be replaced, the German auto company said today.

Only new cars are subject to the measure, a Mercedes spokesman said, adding that customers confronted with the ban will be offered alternate models.

Since Jan. 1, European Union regulations have required that car makers use a cleaner R1234yf refrigerant, deemed less polluting than older products.

But Daimler (IW 1000/18) is sticking to R134a, an older coolant, because it claims studies have shown that the new gas catches fire more easily and puts cars at a greater risk of explosion in the event of a crash.

The makers of R1234yf reject Daimler's claims, but in Germany the auto giant was given special permission to keep using the older gas.

Daimler says it will persist with the older product with the hope that "in the next few years" a safer version will be available.

No country besides France has raised an objection to the continued use of R134a, the Daimler spokesman said.

But last month the European Commission, the EU's executive branch, threatened sanctions against German carmakers for using the refrigerant.

The Commission officially notified Germany of its objections to the continued use of the polluting gas, giving Berlin until September to comply.

Copyright Agence France-Presse, 2013