International rail passenger transport with cabotage has been open to competition since 2010 but subject to two conditions, known as the principal purpose test and the economic equilibrium test. The Commission Implementing Regulation on new rail passenger services adopted on the 11th of July 2014 is a further harmonising step towards a single European railway area. This article investigates the national methodology and procedures developed by ARAF, the French rail regulatory body, and provides a critical analysis of the recently adopted Implementing Regulation. It also raises the issue of a balance of different interests that needs to be found in the methodology to carry out the principal purpose and economic equilibrium test, mainly the equilibrium between the interests of a new entrant and of a competent authority awarding public service contracts. Finally, the article observes that the Commission’s consultation process involved rail regulatory bodies and took into account their proposals but was more limited for other stakeholders.