All 28 Member States of the European Union (EU) are due to meet this Wednesday (17 July) in Brussels to discuss the increasingly pressing issue of France's continued blocking of several Mercedes-Benz models.

The vehicles, A, B and CLA brands, have not been issued registration certificates by France's Systeme d'Immatriculation des Vehicules (SIV) authority as Paris takes issue with Mercedes' use of the r134a refrigerant as opposed to the lower CO2-producing r1234yf alternative.

Mercedes maintains under certain conditions r1234yf can be ignited in extreme situations, but producer, Honeywell, insists its product is safe and points to a European directive mandating the coolant with a global warming potential of less than 150.

"There is a meeting on 17 July - during [it] the European Commission [EC] will meet with the 28 Member States to discuss the Daimler issue and the position of France towards the fact France decided to block the cars by Mercedes," a spokeswoman for EC vice president, responsible for trade, Antonio Tajani, told just-auto from Brussels.

"Tomorrow afternoon, we are probably going to send a release on the position of the European Commission."

The escalating row has been given further impetus by the Commission's decision to send a letter to the German authorities in the form of what it refers to as an "EU pilot infringement procedure" that is attempting to clarify the situation.

Should the German authorities not be able to provide explanations, the Commission says it may: "In its role as Guardian of the Treaty, take the necessary action, including where appropriate, infringement procedures."

Germany, through the auspices of its road safety authority, Kraftfahrt-Bundesamt (KBA), is currently testing the r1234yf refrigerant.

The KBA is the vehicle type approval authority for Germany and although not responsible for testing chemicals themselves, is tasked with certifying car safety.

"The vehicles with 1234yf - these vehicles we are having a risk assessment because Mercedes told this chemical can cause a danger for people inside," a KBA spokesman told just-auto last week from its headquarters in Flensburg, northern Germany.

Honeywell insists its product is "the safest and most environmentally-friendly refrigerant" and has expressed surprise "one company flouts European law in such a flagrant manner," noted the chemical manufacturer's Fluorine Products Europe, Middle East, Africa and India, managing director, Paul Sanders, said.

"All the leading manufacturers were involved in the assessment and everyone approved the use of the new 1234yf refrigerant."

Reports are circulating the German Transport Ministry is asking the European Commission to evaluate whether France's actions are in breach of the EU's free circulation of goods, but no-one from the Berlin-based department was immediately available for comment.