French manufacturers topped the list of European cars and vans with the lowest carbon emissions, the European Environment Agency said in a report published on Thursday.

French vehicle brands Renault, Peugeot and Citroen -- which ranked first, second and third -- had an advantage in the study because average emissions data was evaluated without taking into account the number of cylinders in the engine or the fuel.

France sells smaller engines in southern Europe, and the French market is also dominated by diesel engines, which generate less CO2 than petrol.

In 2014, Renault retained its first place ranking, with 108 grams of carbon dioxide per kilometre (g/km), ahead of Peugeot (110 g/km), which had previously been third behind the Korean Hyundai and Citroen (111 g/km), which had previously been tied at fourth.

The emissions data were based on tests performed in a laboratory setting using a standard European vehicle test cycle. The results might not reflect real-world driving performance, the report said.

Overall, vehicles sold in Europe in 2014 emitted 2.5 percent less CO2 than in 2013, a decrease that remained constant compared to previous years. But this figure excludes Volkswagen after the company admitted in early November that its emissions were 18 percent higher than previously reported.