Paris has escalated a simmering trade row with Germany by formally notifying the European Commission of its move to block the sale of the latest Mercedes models in France.

The commission Friday (2 August) said it would now “assess whether this provisional measure is lawful or not.”

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France filed the notification using EU rules that stipulate that in case of a threat to the environment, member states can take unilateral measures to block the free movement of goods.

Paris argues that Germany is not fulfilling EU climate change obligations.

Under a rule in place since 1 January an air conditioning refrigerant deemed as containing too many greenhouse gases has been banned.

Instead car manufacturers must use a cleaner coolant (R1234yf).

But Germany’s Daimler continues to use the older version (R134a) claiming that studies show that the new one catches fire too easily.

In June, the European Commission threatened Germany with sanction over its breach of the law. Berlin has until 19 August to reply. And the commission a further 10 weeks to reach a decision.

Meanwhile Berlin is said to have lobbied the commission to find France in breach of EU single market rules.

The reaction in Germany to the Mercedes ban has been one of anger. Conservative daily Die Welt suggested France's move was made for protectionist rather than environmental reasons.

But industry commissioner Antonio Tajini indicated earlier this month – before France made the formal notification to the commission – that Paris had good grounds to block A-class, B-class, CLA-class cars that were assembled after 12 June.

“Currently, in the European market, there are vehicles produced by this manufacturer [Daimler] that, according to the preliminary Commission analysis, are not in conformity with their type-approval," he said on 17 July.

"Non-conform vehicles cannot be sold or registered in the European Union," he added.

The commission Friday said there is “no set deadline” for answering to France’s formal notification that it has blocked the cars but that the commission should make a decision “sometime in September.”