The European Commission took Germany to court on Thursday over a controversial road toll system, arguing that it discriminates against drivers from other EU member states.
Last year, Germany decided to introduce a road charging scheme for cars, while also passing a law under which the road charge can be deducted from vehicle taxes for cars registered in Germany.
"If implemented, it will lead to a situation where German users and only German users are de facto exempted from the road charges," said commission spokeswoman Anna-Kaisa Itkonen.
This "fails to comply with ... [EU] principles of non-discrimination based on nationality and the free movement of goods and services," the European Union's executive said in a statement.
The commission has therefore referred the case to the European Court of Justice. The EU's top tribunal can impose hefty fines on countries that fail to fall in line with the bloc's laws.
But German Transport Minister Alexander Dobrindt said Thursday that he expected the court to rule in Berlin's favour, as the so-called infrastructure levy was "compliant with European law."
"Germany now expects a quick lawsuit, so the infrastructure levy can then be technically implemented," Dobrindt said, welcoming the fact that the issue was finally making progress following lengthy discussions with Brussels.
The commission had initiated legal proceedings against Berlin in mid-2015. But its concerns "have not been addressed," it said Thursday.
The scheme was introduced as a concession to Bavaria's Christian Social Union (CSU), a junior partner in Chancellor Angela Merkel's coalition government. Many Bavarians resent road charging in nearby Austria and Switzerland.
Under the planned system, motorists will have buy a sticker costing on average 74 euros (83 dollars) per car in order to use the country's motorways and federal highways.
Dobrindt has estimated that this would bring in 500 million euros annually - money that could be spent on improving German roads.