The latest models of Mercedes cars cannot be sold in France as they still use an air conditioning refrigerant the EU says emits excessive greenhouse gases and should be replaced, the German auto company said on Tuesday.

"Only new cars are subject to the measure," a company spokesman told AFP adding that customers confronted with the ban are to be offered alternate models.

Since January 1, European Union norms demand that car makers use a cleaner R1234yf refrigerant, deemed less polluting than older products.

But Daimler is sticking to R134a, an older coolant, as it claims studies have shown that the new gas catches fire more easily and puts cars at a greater risk of explosion in case 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.

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