The brief alphanumerics R134a and R1234yf are codes for a growing battle between carmakers, states and the EU. The air-conditioning refrigerant R134a has been banned by the EU for being too damaging to the environment, with R1234yf mandated as its replacement. Daimler and Volkswagen say that in their own studies, though, R1234yf can be more dangerous in an accident, potentially starting fires and releasing poisonous hydrogen fluoride gas.
Daimler received dispensation from the German motoring authority KBA to continue using R124a and has refused to put the new refrigerant in its cars, and took that national approval as a European-wide mandate. That has led to France refusing to register all Mercedes-Benz A-, B- and SL-Class vehicles in France that were manufactured after June 12 and filled with the now-banned refrigerant.
In a small victory for Daimler, Reuters reports that a French court decision has lifted the ban on registrations pending a 10-day reexamination of the order. It gives France's environment ministry a period to decide whether to keep the ban in place and return to court to fight for it; it does not, however, require the French authorities to begin registering Mercedes cars. While Mercedes waits to resume sales in France, which could begin again in ten days if France doesn't fight, the EU is threatening Germany with consequences if it refuses to adhere to the federal mandate.