New car prices in Britain are the highest in the 15-nation European Union and British consumers are increasingly travelling abroad to buy cars at lower prices.
EU inspectors raided Renault's French headquarters, the premises of its Irish distributor and several individual dealers on March 24 and 25, said one source.
The news follows the Commission's announcement earlier this week that it formally warned the US-German auto giant DaimlerChrysler that its sales practices in four European countries were in breach of antitrust rules.
British consumers' complaints that cars in Britain are more expensive than anywhere else in the European bloc have increased substantially in the last few years.
These concerns cover all car models, including locally made Rover, but the decision to pick Renault suggests the Commission may be keen to take its offensive beyond the German manufacturers.
Besides DaimlerChrysler, the Commission is investigating General Motors' Opel and last year fined Volkswagen on similar charges.
Renault was not immediately available to comment.
According to the Commission's latest car pricing report, published in February, new car prices in Britain are as much as 45 per cent higher than the cheapest within the bloc.Reuse content